Imported from libpng-0.89.tar

descrip.mms

@@ -10,7 +10,7 @@ pref = /prefix=all
 
 OBJS = png.obj, pngrcb.obj, pngrutil.obj, pngtrans.obj, pngwutil.obj,\
 	pngread.obj, pngmem.obj, pngwrite.obj, pngrtran.obj, pngwtran.obj,\
-	pngio.obj, pngerror.obj, pngpread.obj
+	pngrio.obj, pngwio.obj, pngerror.obj, pngpread.obj
 
 
 CFLAGS= $(C_DEB) $(CC_DEFS) $(PREF)
@@ -41,7 +41,8 @@ pngrtran.obj : png.h, pngconf.h
 pngrutil.obj : png.h, pngconf.h
 pngerror.obj : png.h, pngconf.h
 pngmem.obj : png.h, pngconf.h
-pngio.obj : png.h, pngconf.h
+pngrio.obj : png.h, pngconf.h
+pngwio.obj : png.h, pngconf.h
 pngtest.obj : png.h, pngconf.h
 pngtrans.obj : png.h, pngconf.h
 pngwrite.obj : png.h, pngconf.h

example.c

@@ -48,47 +48,45 @@ void read_png(char *file_name)
    if (!fp)
       return;
 
-   /* allocate the necessary structures */
+   /* Create and initialize the png_struct with the desired error handler
-   png_ptr = malloc(sizeof (png_struct));
+      functions.  If you want to use the default stderr and longjump method,
+      you can supply NULL for the last three parameters.  We also check that
+      the header file is compatible with the library version.
+    */
+   png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+      (void *)user_error_ptr, user_error_fn, user_warning_fn);
+
    if (!png_ptr)
    {
       fclose(fp);
       return;
    }
 
-   info_ptr = malloc(sizeof (png_info));
+   info_ptr = png_create_info_struct();
    if (!info_ptr)
    {
       fclose(fp);
-      free(png_ptr);
+      png_destroy_read_struct(&png_ptr,  (png_infopp)NULL, (png_infopp)NULL);
       return;
    }
 
-   /* set error handling */
+   /* set error handling if you are using the setjmp/longjmp method */
    if (setjmp(png_ptr->jmpbuf))
    {
-      png_read_destroy(png_ptr, info_ptr, (png_info *)0);
+      /* Free all of the memory associated with the png_ptr and info_ptr */
+      png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
       fclose(fp);
-      free(png_ptr);
-      free(info_ptr);
       /* If we get here, we had a problem reading the file */
       return;
    }
 
-   /* initialize the structures, info first for error handling */
-   png_info_init(info_ptr);
-   png_read_init(png_ptr);
-
    /* set up the input control if you are using standard C streams */
    png_init_io(png_ptr, fp);
 
-   /* if you are using replacement read functions, here you would call */
+   /* if you are using replacement read functions, instead of calling
-   png_set_read_fn(png_ptr, (void *)io_ptr, user_read_fn);
+      png_init_io() here you would call */
-   /* where io_ptr is a structure you want available to the callbacks */
+   png_set_read_fn(png_ptr, (void *)user_io_ptr, user_read_fn);
-
+   /* where user_io_ptr is a structure you want available to the callbacks */
-   /* if you are using replacement message functions, here you would call */
-   png_set_message_fn(png_ptr, (void *)msg_ptr, user_error_fn, user_warning_fn);
-   /* where msg_ptr is a structure you want available to the callbacks */
 
    /* read the file information */
    png_read_info(png_ptr, info_ptr);
@@ -96,21 +94,23 @@ void read_png(char *file_name)
    /* set up the transformations you want.  Note that these are
       all optional.  Only call them if you want them */
 
-   /* expand paletted colors into true rgb */
+   /* expand paletted colors into true RGB triplets */
    if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       png_set_expand(png_ptr);
 
    /* expand grayscale images to the full 8 bits */
-   if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY &&
+   if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY && info_ptr->bit_depth < 8)
-      info_ptr->bit_depth < 8)
       png_set_expand(png_ptr);
 
-   /* expand images with transparency to full alpha channels */
+   /* expand paletted or RGB images with transparency to full alpha channels
+    * so the data will be available as RGBA quartets */
    if (info_ptr->valid & PNG_INFO_tRNS)
       png_set_expand(png_ptr);
 
    /* Set the background color to draw transparent and alpha
-      images over */
+      images over.  It is possible to set the red, green, and blue
+      components directly for paletted images. */
+
    png_color_16 my_background;
 
    if (info_ptr->valid & PNG_INFO_bKGD)
@@ -126,18 +126,17 @@ void read_png(char *file_name)
    else
       png_set_gamma(png_ptr, screen_gamma, 0.45);
 
-   /* tell libpng to strip 16 bit depth files down to 8 bits */
+   /* tell libpng to strip 16 bit/color files down to 8 bits/color */
    if (info_ptr->bit_depth == 16)
       png_set_strip_16(png_ptr);
 
-   /* dither rgb files down to 8 bit palettes & reduce palettes
+   /* dither rgb files down to 8 bit palette & reduce palettes
       to the number of colors available on your screen */
    if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
    {
       if (info_ptr->valid & PNG_INFO_PLTE)
-         png_set_dither(png_ptr, info_ptr->palette,
+         png_set_dither(png_ptr, info_ptr->palette, info_ptr->num_palette,
-            info_ptr->num_palette, max_screen_colors,
+                        max_screen_colors, info_ptr->histogram);
-               info_ptr->histogram);
       else
       {
          png_color std_color_cube[MAX_SCREEN_COLORS] =
@@ -148,9 +147,8 @@ void read_png(char *file_name)
       }
    }
 
-   /* invert monocrome files */
+   /* invert monocrome files to have 0 as white and 1 as black */
-   if (info_ptr->bit_depth == 1 &&
+   if (info_ptr->bit_depth == 1 && info_ptr->color_type == PNG_COLOR_GRAY)
-      info_ptr->color_type == PNG_COLOR_GRAY)
       png_set_invert(png_ptr);
 
    /* shift the pixels down to their true bit depth */
@@ -158,7 +156,8 @@ void read_png(char *file_name)
       info_ptr->bit_depth > info_ptr->sig_bit)
       png_set_shift(png_ptr, &(info_ptr->sig_bit));
 
-   /* pack pixels into bytes */
+   /* pack multiple pixels with bit depths of 1, 2, and 4 into bytes
+      (useful only for paletted and grayscale images) */
    if (info_ptr->bit_depth < 8)
       png_set_packing(png_ptr);
 
@@ -171,21 +170,15 @@ void read_png(char *file_name)
    if (info_ptr->bit_depth == 16)
       png_set_swap(png_ptr);
 
-   /* add a filler byte to rgb files */
+   /* add a filler byte to RGB files (before or after each RGB triplet) */
-   if (info_ptr->bit_depth == 8 &&
+   if (info_ptr->bit_depth == 8 && info_ptr->color_type == PNG_COLOR_TYPE_RGB)
-      info_ptr->color_type == PNG_COLOR_TYPE_RGB)
       png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
 
    /* turn on interlace handling if you are not using png_read_image() */
-   if (info_ptr->interlace_type)
    number_passes = png_set_interlace_handling(png_ptr);
-   else
-      number_passes = 1;
 
-   /* optional call to update palette with transformations */
+   /* optional call to gamma correct and add the background to the palette
-   png_start_read_image(png_ptr);
+      and update info structure. */
-
-   /* optional call to update the info structure */
    png_read_update_info(png_ptr, info_ptr);
 
    /* allocate the memory to hold the image using the fields
@@ -193,6 +186,12 @@ void read_png(char *file_name)
 
    /* the easiest way to read the image */
    png_bytep row_pointers[height];
+
+   for (row = 0; row < height; row++)
+   {
+     row_pointers[row] = malloc(info_ptr->rowbytes);
+   }
+
    png_read_image(png_ptr, row_pointers);
 
    /* the other way to read images - deal with interlacing */
@@ -216,16 +215,11 @@ void read_png(char *file_name)
          so here */
    }
 
-   /* read the rest of the file, getting any additional chunks
+   /* read the rest of the file, getting any additional chunks in info_ptr */
-      in info_ptr */
    png_read_end(png_ptr, info_ptr);
 
    /* clean up after the read, and free any memory allocated */
-   png_read_destroy(png_ptr, info_ptr, (png_infop)0);
+   png_destroy_read_struct(&png_ptr, &info_ptr, (png_infopp)NULL);
-
-   /* free the structures */
-   free(png_ptr);
-   free(info_ptr);
 
    /* close the file */
    fclose(fp);
@@ -236,68 +230,74 @@ void read_png(char *file_name)
 
 /* progressively read a file */
 
-/* these will normally not be global unless you are only
-   reading in one image at a time */
-png_structp png_ptr;
-png_infop info_ptr;
-
 int
-initialize_png_reader()
+initialize_png_reader(png_structp *png_ptr, png_infop *info_ptr)
 {
-   png_ptr = malloc(sizeof (png_struct));
+   /* Create and initialize the png_struct with the desired error handler
-   if (!png_ptr)
+      functions.  If you want to use the default stderr and longjump method,
-      return -1;
+      you can supply NULL for the last three parameters.  We also check that
-   info_ptr = malloc(sizeof (png_info));
+      the library version is compatible in case we are using dynamically
-   if (!info_ptr)
+      linked libraries.
+    */
+   *png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
+       (void *)user_error_ptr, user_error_fn, user_warning_fn);
+
+   if (! *png_ptr)
    {
-      free(png_ptr);
+      *info_ptr = NULL;
-      return -1;
+      return ERROR;
    }
 
-   if (setjmp(png_ptr->jmpbuf))
+   *info_ptr = png_create_info_struct(png_ptr);
+
+   if (! *info_ptr)
    {
-      png_read_destroy(png_ptr, info_ptr, (png_info *)0);
+      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
-      /* free pointers before returning, if necessary */
+      return ERROR;
-      free(png_ptr);
-      free(info_ptr);
-      return -1;
    }
 
-   png_info_init(info_ptr);
+   if (setjmp((*png_ptr)->jmpbuf))
-   png_read_init(png_ptr);
+   {
+      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
+      return ERROR;
+   }
 
    /* this one's new.  You will need to provide all three
       function callbacks, even if you aren't using them all.
-      You can put a void pointer in place of the NULL, and
+      These functions shouldn't be dependent on global or
-      retrieve the pointer from inside the callbacks using
+      static variables if you are decoding several images
-      the function png_get_progressive_ptr(png_ptr); */
+      simultaneously.  You should store stream specific data
-   png_set_progressive_read_fn(png_ptr, NULL,
+      in a separate struct, given as the second parameter,
+      and retrieve the pointer from inside the callbacks using
+      the function png_get_progressive_ptr(png_ptr). */
+   png_set_progressive_read_fn(*png_ptr, (void *)stream_data,
       info_callback, row_callback, end_callback);
 
-   return 0;
+   return OK;
 }
 
 int
-process_data(png_bytep buffer, png_uint_32 length)
+process_data(png_structp *png_ptr, png_infop *info_ptr,
+   png_bytep buffer, png_uint_32 length)
 {
-   if (setjmp(png_ptr->jmpbuf))
+   if (setjmp((*png_ptr)->jmpbuf))
    {
-      png_read_destroy(png_ptr, info_ptr, (png_info *)0);
+      /* Free the png_ptr and info_ptr memory on error */
-      free(png_ptr);
+      png_destroy_read_struct(png_ptr, info_ptr, (png_infopp)NULL);
-      free(info_ptr);
+      return ERROR;
-      return -1;
    }
 
-   /* this one's new also.  Simply give it a chunk of data
+   /* this one's new also.  Simply give it chunks of data as
-      from the file stream (in order, of course).  On Segmented
+      they arrive from the data stream (in order, of course).
-      machines, don't give it any more then 64K.  The library
+      On Segmented machines, don't give it any more than 64K.
-      seems to run fine with sizes of 4K, although you can give
+      The library seems to run fine with sizes of 4K, although
-      it much less if necessary (I assume you can give it chunks
+      you can give it much less if necessary (I assume you can
-      of 1 byte, but I haven't tried less then 256 bytes yet).
+      give it chunks of 1 byte, but I haven't tried with less
-      When this function returns, you may want to display any
+      than 256 bytes yet).  When this function returns, you may
-      rows that were generated in the row callback. */
+      want to display any rows that were generated in the row
-   png_process_data(png_ptr, info_ptr, buffer, length);
+      callback, if you aren't already displaying them there. */
-   return 0;
+   png_process_data(*png_ptr, *info_ptr, buffer, length);
+   return OK;
 }
 
 info_callback(png_structp png_ptr, png_infop info)
@@ -363,44 +363,41 @@ void write_png(char *file_name, ... other image information ...)
    if (!fp)
       return;
 
-   /* allocate the necessary structures */
+   /* Create and initialize the png_struct with the desired error handler
-   png_ptr = malloc(sizeof (png_struct));
+      functions.  If you want to use the default stderr and longjump method,
+      you can supply NULL for the last three parameters.  We also check that
+      the library version is compatible in case we are using dynamically
+      linked libraries.
+    */
+   png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+      (void *)user_error_ptr, user_error_fn, user_warning_fn);
+
    if (!png_ptr)
    {
       fclose(fp);
       return;
    }
 
-   info_ptr = malloc(sizeof (png_info));
+   info_ptr = png_create_info_struct(png_ptr);
    if (!info_ptr)
    {
       fclose(fp);
-      free(png_ptr);
+      png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
       return;
    }
 
    /* set error handling */
    if (setjmp(png_ptr->jmpbuf))
    {
-      png_write_destroy(png_ptr);
-      fclose(fp);
-      free(png_ptr);
-      free(info_ptr);
       /* If we get here, we had a problem reading the file */
+      fclose(fp);
+      png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
       return;
    }
 
-   /* initialize the structures */
-   png_info_init(info_ptr);
-   png_write_init(png_ptr);
-
    /* set up the output control if you are using standard C streams */
    png_init_io(png_ptr, fp);
 
-   /* if you are using replacement write functions, here you would call */
-   png_set_write_fn(png_ptr, (void *)io_ptr, user_write_fn, user_flush_fn);
-   /* where io_ptr is a structure you want available to the callbacks */
-
    /* if you are using replacement message functions, here you would call */
    png_set_message_fn(png_ptr, (void *)msg_ptr, user_error_fn, user_warning_fn);
    /* where msg_ptr is a structure you want available to the callbacks */
@@ -432,9 +429,9 @@ void write_png(char *file_name, ... other image information ...)
    info_ptr->valid |= PNG_INFO_gAMA;
    info_ptr->gamma = gamma;
 
-   /* other optional chunks */
+   /* other optional chunks like cHRM, bKGD, tRNS, tEXt, tIME, oFFs, pHYs, */
 
-   /* write the file information */
+   /* write the file header information */
    png_write_info(png_ptr, info_ptr);
 
    /* set up the transformations you want.  Note that these are
@@ -466,8 +463,10 @@ void write_png(char *file_name, ... other image information ...)
    else
       number_passes = 1;
 
-   /* the easiest way to write the image */
+   /* the easiest way to write the image (you may choose to allocate the
-   png_bytep row_pointers[height];
+      memory differently, however) */
+   png_byte row_pointers[height][width];
+
    png_write_image(png_ptr, row_pointers);
 
    /* the other way to write the image - deal with interlacing */
@@ -485,19 +484,23 @@ void write_png(char *file_name, ... other image information ...)
       }
    }
 
+   /* You can write optional chunks like tEXt, tIME at the end as well.
+    * Note that if you wrote tEXt or zTXt chunks before the image, and
+    * you aren't writing out more at the end, you have to set
+    * info_ptr->num_text = 0 or they will be written out again.
+    */
+
    /* write the rest of the file */
    png_write_end(png_ptr, info_ptr);
 
-   /* clean up after the write, and free any memory allocated */
-   png_write_destroy(png_ptr);
-
    /* if you malloced the palette, free it here */
    if (info_ptr->palette)
       free(info_ptr->palette);
 
-   /* free the structures */
+   /* if you allocated any text comments, free them here */
-   free(png_ptr);
+
-   free(info_ptr);
+   /* clean up after the write, and free any memory allocated */
+   png_destroy_write_struct(&png_ptr,  (png_infopp)NULL);
 
    /* close the file */
    fclose(fp);

makefile

@@ -13,8 +13,8 @@ RANLIB=echo
 prefix=/usr/local
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o
-   pngmem.o pngerror.o pngpread.o
+	pngwtran.o pngmem.o pngerror.o pngpread.o
 
 all: libpng.a pngtest
 
@@ -45,7 +45,8 @@ clean:
 
 png.o: png.h pngconf.h
 pngerror.o: png.h pngconf.h
-pngio.o: png.h pngconf.h
+pngrio.o: png.h pngconf.h
+pngwio.o: png.h pngconf.h
 pngmem.o: png.h pngconf.h
 pngrcb.o: png.h pngconf.h
 pngread.o: png.h pngconf.h

makefile.aco

@@ -0,0 +1,114 @@
+# Project:   libpng
+
+
+# Toolflags:
+CCflags = -c -depend !Depend -IC:,Zlib: -g -throwback  -DRISCOS  -fnah 
+C++flags = -c -depend !Depend -IC: -throwback
+Linkflags = -aif -c++ -o $@
+ObjAsmflags = -throwback -NoCache -depend !Depend
+CMHGflags = 
+LibFileflags = -c -o $@ 
+Squeezeflags = -o $@
+
+
+# Final targets:
+@.libpng-lib:   @.o.png @.o.pngerror @.o.pngrio @.o.pngwio @.o.pngmem \
+        @.o.pngpread @.o.pngrcb @.o.pngread @.o.pngrtran @.o.pngrutil \
+        @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil
+        LibFile $(LibFileflags) @.o.png @.o.pngerror @.o.pngrio @.o.pngwio \
+        @.o.pngmem @.o.pngpread @.o.pngrcb @.o.pngread @.o.pngrtran \
+        @.o.pngrutil @.o.pngtrans @.o.pngwrite @.o.pngwtran @.o.pngwutil 
+@.test:   @.tests.pngtest 
+        echo Please run "Test" in directory tests 
+@.tests.pngtest:   @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib 
+        Link $(Linkflags) @.o.pngtest @.libpng-lib C:o.Stubs Zlib:zlib_lib 
+
+
+# User-editable dependencies:
+.c.o:
+        cc $(ccflags) -o $@ $<
+
+
+# Static dependencies:
+@.o.example:   @.tests.c.example
+        cc $(ccflags) -o @.o.example @.tests.c.example 
+@.o.pngtest:   @.tests.c.pngtest
+        cc $(ccflags) -o @.o.pngtest @.tests.c.pngtest 
+
+
+# Dynamic dependencies:
+o.png:	c.png
+o.png:	h.png
+o.png:	Zlib:h.zlib
+o.png:	Zlib:h.zconf
+o.png:	h.pngconf
+o.pngerror:	c.pngerror
+o.pngerror:	h.png
+o.pngerror:	Zlib:h.zlib
+o.pngerror:	Zlib:h.zconf
+o.pngerror:	h.pngconf
+o.pngrio:	c.pngrio
+o.pngrio:	h.png
+o.pngrio:	Zlib:h.zlib
+o.pngrio:	Zlib:h.zconf
+o.pngrio:	h.pngconf
+o.pngwio:	c.pngwio
+o.pngwio:	h.png
+o.pngwio:	Zlib:h.zlib
+o.pngwio:	Zlib:h.zconf
+o.pngwio:	h.pngconf
+o.pngmem:	c.pngmem
+o.pngmem:	h.png
+o.pngmem:	Zlib:h.zlib
+o.pngmem:	Zlib:h.zconf
+o.pngmem:	h.pngconf
+o.pngpread:	c.pngpread
+o.pngpread:	h.png
+o.pngpread:	Zlib:h.zlib
+o.pngpread:	Zlib:h.zconf
+o.pngpread:	h.pngconf
+o.pngrcb:	c.pngrcb
+o.pngrcb:	h.png
+o.pngrcb:	Zlib:h.zlib
+o.pngrcb:	Zlib:h.zconf
+o.pngrcb:	h.pngconf
+o.pngread:	c.pngread
+o.pngread:	h.png
+o.pngread:	Zlib:h.zlib
+o.pngread:	Zlib:h.zconf
+o.pngread:	h.pngconf
+o.pngrtran:	c.pngrtran
+o.pngrtran:	h.png
+o.pngrtran:	Zlib:h.zlib
+o.pngrtran:	Zlib:h.zconf
+o.pngrtran:	h.pngconf
+o.pngrutil:	c.pngrutil
+o.pngrutil:	h.png
+o.pngrutil:	Zlib:h.zlib
+o.pngrutil:	Zlib:h.zconf
+o.pngrutil:	h.pngconf
+o.pngtrans:	c.pngtrans
+o.pngtrans:	h.png
+o.pngtrans:	Zlib:h.zlib
+o.pngtrans:	Zlib:h.zconf
+o.pngtrans:	h.pngconf
+o.pngwrite:	c.pngwrite
+o.pngwrite:	h.png
+o.pngwrite:	Zlib:h.zlib
+o.pngwrite:	Zlib:h.zconf
+o.pngwrite:	h.pngconf
+o.pngwtran:	c.pngwtran
+o.pngwtran:	h.png
+o.pngwtran:	Zlib:h.zlib
+o.pngwtran:	Zlib:h.zconf
+o.pngwtran:	h.pngconf
+o.pngwutil:	c.pngwutil
+o.pngwutil:	h.png
+o.pngwutil:	Zlib:h.zlib
+o.pngwutil:	Zlib:h.zconf
+o.pngwutil:	h.pngconf
+o.pngtest:	tests.c.pngtest
+o.pngtest:	h.png
+o.pngtest:	Zlib:h.zlib
+o.pngtest:	Zlib:h.zconf
+o.pngtest:	h.pngconf

makefile.ama

@@ -23,7 +23,7 @@ AR= oml
 MKDIR= makedir
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o pngpread.o \
-pngread.o pngerror.o pngwrite.o pngrtran.o pngwtran.o pngio.o pngmem.o
+pngread.o pngerror.o pngwrite.o pngrtran.o pngwtran.o pngrio.o pngwio.o pngmem.o
 
 all: libpng.lib pngtest
 

makefile.atr

@@ -14,7 +14,7 @@ OBJS = $(LBR)(png.o) $(LBR)(pngrcb.o) $(LBR)(pngrutil.o)\
 	$(LBR)(pngtrans.o) $(LBR)(pngwutil.o)\
 	$(LBR)(pngread.o) $(LBR)(pngerror.o) $(LBR)(pngwrite.o)\
 	$(LBR)(pngrtran.o) $(LBR)(pngwtran.o)\
-   $(LBR)(pngmem.o) $(LBR)(pngio.o) $(LBR)(pngpread.o)
+	$(LBR)(pngmem.o) $(LBR)(pngrio.o) $(LBR)(pngwio.o) $(LBR)(pngpread.o)
 
 all: $(LBR) pngtest.ttp
 

makefile.bor

@@ -71,35 +71,35 @@ O=obj
 ## variables
 OBJS = \
  png.$(O) \
+ pngerror.$(O) \
+ pngmem.$(O) \
+ pngpread.$(O) \
  pngrcb.$(O) \
+ pngread.$(O) \
+ pngrio.$(O) \
+ pngrtran.$(O) \
  pngrutil.$(O) \
  pngtrans.$(O) \
- pngwutil.$(O) \
- pngmem.$(O) \
- pngread.$(O) \
- pngpread.$(O) \
- pngerror.$(O) \
  pngwrite.$(O) \
- pngrtran.$(O) \
  pngwtran.$(O) \
- pngzlib.$(O) \
+ pngwio.$(O) \
- pngio.$(O)
+ pngwutil.$(O)
 
 LIBOBJS = \
  +png.$(O) \
- +pngrcb.$(O) \
+ +pngerror.$(O) \
- +pngrutil.$(O) \
- +pngtrans.$(O) \
- +pngwutil.$(O) \
  +pngmem.$(O) \
  +pngpread.$(O) \
  +pngread.$(O) \
- +pngerror.$(O) \
+ +pngrcb.$(O) \
- +pngwrite.$(O) \
+ +pngrio.$(O) \
  +pngrtran.$(O) \
+ +pngrutil.$(O) \
+ +pngtrans.$(O) \
+ +pngwrite.$(O) \
  +pngwtran.$(O) \
- +pngzlib.$(O) \
+ +pngwio.$(O)
- +pngio.$(O)
+ +pngwutil.$(O)
 
 LIBNAME=libpng$(MODEL).lib
 
@@ -133,12 +133,12 @@ pngrtran.obj: pngrtran.c
 pngrutil.obj: pngrutil.c
 pngerror.obj: pngerror.c
 pngmem.obj: pngmem.c
-pngio.obj: pngio.c
+pngrio.obj: pngrio.c
+pngwio.obj: pngwio.c
 pngtrans.obj: pngtrans.c
 pngwrite.obj: pngwrite.c
 pngwtran.obj: pngwtran.c
 pngwutil.obj: pngwutil.c
-pngzlib.obj: pngzlib.c
 
 
 $(LIBNAME): $(OBJS)

makefile.elf

@@ -4,19 +4,19 @@
 
 CC=gcc
 CFLAGS=-I../zlib -O2 -Wall -fPIC
-LDFLAGS=-L. -L../zlib/ -lpng -lz -lm
+LDFLAGS=-L. -Wl,-rpath,. -L../zlib/ -Wl,-rpath,../zlib/ -lpng -lz -lm
 
 RANLIB=ranlib
 #RANLIB=echo
 
-PNGVER = 0.86
+PNGVER = 0.89
 
 # where make install puts libpng.a, libpng.so*, and png.h
 prefix=/usr/local
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
-       pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+       pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-       pngmem.o pngerror.o pngpread.o
+       pngwtran.o pngmem.o pngerror.o pngpread.o
 
 all: libpng.so pngtest
 
@@ -59,7 +59,8 @@ clean:
 
 png.o: png.h pngconf.h
 pngerror.o: png.h pngconf.h
-pngio.o: png.h pngconf.h
+pngrio.o: png.h pngconf.h
+pngwio.o: png.h pngconf.h
 pngmem.o: png.h pngconf.h
 pngrcb.o: png.h pngconf.h
 pngread.o: png.h pngconf.h

makefile.gcc

@@ -13,7 +13,7 @@ RANLIB=ranlib
 prefix=.
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o pngwtran.o \
 	pngmem.o pngerror.o pngpread.o
 
 all: libpng.a pngtest
@@ -35,7 +35,8 @@ clean:
 
 png.o: png.h pngconf.h
 pngerror.o: png.h pngconf.h
-pngio.o: png.h pngconf.h
+pngrio.o: png.h pngconf.h
+pngwio.o: png.h pngconf.h
 pngmem.o: png.h pngconf.h
 pngrcb.o: png.h pngconf.h
 pngread.o: png.h pngconf.h

makefile.knr

@@ -15,8 +15,8 @@ RANLIB=ranlib
 prefix=/usr/local
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-   pngmem.o pngerror.o pngpread.o
+	pngwtran.o pngmem.o pngerror.o pngpread.o
 
 all: ansi2knr libpng.a pngtest
 
@@ -57,7 +57,8 @@ clean:
 
 png.o: png.h pngconf.h
 pngerror.o: png.h pngconf.h
-pngio.o: png.h pngconf.h
+pngrio.o: png.h pngconf.h
+pngwio.o: png.h pngconf.h
 pngmem.o: png.h pngconf.h
 pngrcb.o: png.h pngconf.h
 pngread.o: png.h pngconf.h

makefile.mip

@@ -14,8 +14,8 @@ RANLIB=echo
 prefix=/usr/local
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-   pngmem.o pngerror.o pngpread.o
+	pngwtran.o pngmem.o pngerror.o pngpread.o
 
 all: libpng.a pngtest
 
@@ -46,7 +46,8 @@ clean:
 
 png.o: png.h pngconf.h
 pngerror.o: png.h pngconf.h
-pngio.o: png.h pngconf.h
+pngrio.o: png.h pngconf.h
+pngwio.o: png.h pngconf.h
 pngmem.o: png.h pngconf.h
 pngrcb.o: png.h pngconf.h
 pngread.o: png.h pngconf.h

makefile.msc

@@ -17,7 +17,7 @@ ERRFILE= >> pngerrs
 
 # variables
 OBJS1 = png$(O) pngrcb$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O) pngmem$(O) pngpread$(O)
-OBJS2 = pngread$(O) pngerror$(O) pngwrite$(O) pngrtran$(O) pngwtran$(O) pngio$(O)
+OBJS2 = pngread$(O) pngerror$(O) pngwrite$(O) pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)
 
 all: libpng.lib
 
@@ -45,7 +45,10 @@ pngerror$(O): png.h pngconf.h
 pngmem$(O): png.h pngconf.h
         $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
 
-pngio$(O): png.h pngconf.h
+pngrio$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
+
+pngwio$(O): png.h pngconf.h
         $(CC) -c $(CFLAGS) $*.c $(ERRFILE)
 
 pngtest$(O): png.h pngconf.h

makefile.std

@@ -13,8 +13,8 @@ RANLIB=echo
 prefix=/usr/local
 
 OBJS = png.o pngrcb.o pngrutil.o pngtrans.o pngwutil.o \
-	pngread.o pngio.o pngwrite.o pngrtran.o pngwtran.o \
+	pngread.o pngrio.o pngwio.o pngwrite.o pngrtran.o \
-   pngmem.o pngerror.o pngpread.o
+	pngwtran.o pngmem.o pngerror.o pngpread.o
 
 all: libpng.a pngtest
 
@@ -45,7 +45,8 @@ clean:
 
 png.o: png.h pngconf.h
 pngerror.o: png.h pngconf.h
-pngio.o: png.h pngconf.h
+pngrio.o: png.h pngconf.h
+pngwio.o: png.h pngconf.h
 pngmem.o: png.h pngconf.h
 pngrcb.o: png.h pngconf.h
 pngread.o: png.h pngconf.h

makefile.tc

@@ -14,9 +14,9 @@ O=.obj
 
 # variables
 OBJS1 = png$(O) pngrcb$(O) pngrutil$(O) pngtrans$(O) pngwutil$(O) pngmem$(O) pngpread$(O)
-OBJS2 = pngread$(O) pngerror$(O) pngwrite$(O) pngrtran$(O) pngwtran$(O) pngio$(O)
+OBJS2 = pngread$(O) pngerror$(O) pngwrite$(O) pngrtran$(O) pngwtran$(O) pngrio$(O) pngwio$(O)
 OBJSL1 = +png$(O) +pngrcb$(O) +pngrutil$(O) +pngtrans$(O) +pngwutil$(O) +pngmem$(O) +pngpread$(O)
-OBJSL2 = +pngread$(O) +pngerror$(O) +pngwrite$(O) +pngrtran$(O) +pngwtran$(O) pngio$(O)
+OBJSL2 = +pngread$(O) +pngerror$(O) +pngwrite$(O) +pngrtran$(O) +pngwtran$(O) +pngrio$(O) +pngwio$(O)
 
 all: libpng.lib
 
@@ -44,7 +44,10 @@ pngerror$(O): png.h pngconf.h
 pngmem$(O): png.h pngconf.h
         $(CC) -c $(CFLAGS) $*.c
 
-pngio$(O): png.h pngconf.h
+pngrio$(O): png.h pngconf.h
+        $(CC) -c $(CFLAGS) $*.c
+
+pngwio$(O): png.h pngconf.h
         $(CC) -c $(CFLAGS) $*.c
 
 pngtest$(O): png.h pngconf.h

makevms.com

@@ -52,8 +52,10 @@ $   CALL MAKE pngerror.OBJ "cc ''CCOPT' pngerror" -
                 pngerror.c png.h pngconf.h
 $   CALL MAKE pngmem.OBJ "cc ''CCOPT' pngmem" -
                 pngmem.c png.h pngconf.h
-$   CALL MAKE pngio.OBJ "cc ''CCOPT' pngio" -
+$   CALL MAKE pngrio.OBJ "cc ''CCOPT' pngrio" -
-                pngio.c png.h pngconf.h
+                pngrio.c png.h pngconf.h
+$   CALL MAKE pngwio.OBJ "cc ''CCOPT' pngwio" -
+                pngwio.c png.h pngconf.h
 $   CALL MAKE pngtrans.OBJ "cc ''CCOPT' pngtrans" -
                 pngtrans.c png.h pngconf.h
 $   CALL MAKE pngwrite.OBJ "cc ''CCOPT' pngwrite" -

png.c

@@ -1,10 +1,10 @@
 
 /* png.c - location for general purpose png functions
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -13,7 +13,7 @@
 
 /* version information for c files.  This better match the version
    string defined in png.h */
-char png_libpng_ver[] = "0.88";
+char png_libpng_ver[] = "0.89";
 
 /* place to hold the signiture string for a png file. */
 png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
@@ -25,39 +25,17 @@ png_byte FARDATA png_IHDR[4] = { 73,  72,  68,  82};
 png_byte FARDATA png_IDAT[4] = { 73,  68,  65,  84};
 png_byte FARDATA png_IEND[4] = { 73,  69,  78,  68};
 png_byte FARDATA png_PLTE[4] = { 80,  76,  84,  69};
-#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_WRITE_gAMA_SUPPORTED)
 png_byte FARDATA png_gAMA[4] = {103,  65,  77,  65};
-#endif
-#if defined(PNG_READ_sBIT_SUPPORTED) || defined(PNG_WRITE_sBIT_SUPPORTED)
 png_byte FARDATA png_sBIT[4] = {115,  66,  73,  84};
-#endif
-#if defined(PNG_READ_cHRM_SUPPORTED) || defined(PNG_WRITE_cHRM_SUPPORTED)
 png_byte FARDATA png_cHRM[4] = { 99,  72,  82,  77};
-#endif
-#if defined(PNG_READ_tRNS_SUPPORTED) || defined(PNG_WRITE_tRNS_SUPPORTED)
 png_byte FARDATA png_tRNS[4] = {116,  82,  78,  83};
-#endif
-#if defined(PNG_READ_bKGD_SUPPORTED) || defined(PNG_WRITE_bKGD_SUPPORTED)
 png_byte FARDATA png_bKGD[4] = { 98,  75,  71,  68};
-#endif
-#if defined(PNG_READ_hIST_SUPPORTED) || defined(PNG_WRITE_hIST_SUPPORTED)
 png_byte FARDATA png_hIST[4] = {104,  73,  83,  84};
-#endif
-#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_WRITE_tEXt_SUPPORTED)
 png_byte FARDATA png_tEXt[4] = {116,  69,  88, 116};
-#endif
-#if defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
 png_byte FARDATA png_zTXt[4] = {122,  84,  88, 116};
-#endif
-#if defined(PNG_READ_pHYs_SUPPORTED) || defined(PNG_WRITE_pHYs_SUPPORTED)
 png_byte FARDATA png_pHYs[4] = {112,  72,  89, 115};
-#endif
-#if defined(PNG_READ_oFFs_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
 png_byte FARDATA png_oFFs[4] = {111,  70,  70, 115};
-#endif
-#if defined(PNG_READ_tIME_SUPPORTED) || defined(PNG_WRITE_tIME_SUPPORTED)
 png_byte FARDATA png_tIME[4] = {116,  73,  77,  69};
-#endif
 
 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
 
@@ -209,6 +187,21 @@ png_calculate_crc(png_structp png_ptr, png_bytep ptr,
 {
    png_ptr->crc = update_crc(png_ptr->crc, ptr, length);
 }
+
+png_infop
+png_create_info_struct(png_structp png_ptr)
+{
+   png_infop info_ptr;
+
+   if ((info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO)) != NULL)
+   {
+      png_memset(info_ptr, 0, sizeof(png_info));
+      png_ptr->do_free |= PNG_FREE_INFO;
+   }
+
+   return info_ptr;
+}
+
 void
 png_info_init(png_infop info)
 {
@@ -216,3 +209,20 @@ png_info_init(png_infop info)
    png_memset(info, 0, sizeof (png_info));
 }
 
+/* This function returns a pointer to the io_ptr associated with the user
+   functions.  The application should free any memory associated with this
+   pointer before png_write_destroy and png_read_destroy are called. */
+png_voidp
+png_get_io_ptr(png_structp png_ptr)
+{
+   return png_ptr->io_ptr;
+}
+ 
+/* Initialize the default input/output functions for the png file.  If you
+   change the read, or write routines, you can call either png_set_read_fn()
+   or png_set_write_fn() instead of png_init_io(). */
+void
+png_init_io(png_structp png_ptr, FILE *fp)
+{
+   png_ptr->io_ptr = (png_voidp)fp;
+}

png.h

@@ -1,8 +1,8 @@
 
 /* png.h - header file for png reference library
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
-   Jan 25, 1996
+   May 25, 1996
 
    Note: This is a beta version.  It reads and writes valid files
    on the platforms I have, but it has had limited portability
@@ -74,10 +74,10 @@
 
 /* version information for png.h - this should match the version
    number in png.c */
-#define PNG_LIBPNG_VER_STRING "0.88"
+#define PNG_LIBPNG_VER_STRING "0.89"
-/* careful here.  I wanted to use 088, but that would be octal.  Version
+/* careful here.  I wanted to use 089, but that would be octal.  Version
    1.0 will be 100 here, etc. */
-#define PNG_LIBPNG_VER 88
+#define PNG_LIBPNG_VER 89
 
 /* variables defined in png.c - only it needs to define PNG_NO_EXTERN */
 #ifndef PNG_NO_EXTERN
@@ -88,11 +88,7 @@ extern char png_libpng_ver[];
 
 /* three color definitions.  The order of the red, green, and blue, (and the
    exact size) is not important, although the size of the fields need to
-   be png_byte or png_uint_16 (as defined below).  While png_color_8 and
+   be png_byte or png_uint_16 (as defined below).  */
-   png_color_16 have more fields then they need, they are never used in
-   arrays, so the size isn't that important.  I thought about using
-   unions, but it looked too clumsy, so I left it. If you're using C++,
-   you can union red, index, and gray, if you really want too. */
 typedef struct png_color_struct
 {
    png_byte red;
@@ -144,7 +140,6 @@ typedef struct png_time_struct
 {
    png_uint_16 year; /* full year, as in, 1995 */
    png_byte month; /* month of year, 1 - 12 */
-
    png_byte day; /* day of month, 1 - 31 */
    png_byte hour; /* hour of day, 0 - 23 */
    png_byte minute; /* minute of hour, 0 - 59 */
@@ -165,18 +160,22 @@ typedef struct png_info_struct
    /* the following are necessary for every png file */
    png_uint_32 width; /* with of file */
    png_uint_32 height; /* height of file */
+   png_uint_32 valid; /* the PNG_INFO_ defines, OR'd together */
+   png_uint_32 rowbytes; /* bytes needed for untransformed row */
+   png_colorp palette; /* palette of file */
+   png_uint_16 num_palette; /* number of values in palette */
+   png_uint_16 num_trans; /* number of trans values */
    png_byte bit_depth; /* 1, 2, 4, 8, or 16 */
    png_byte color_type; /* use the PNG_COLOR_TYPE_ defines */
    png_byte compression_type; /* must be 0 */
    png_byte filter_type; /* must be 0 */
    png_byte interlace_type; /* 0 for non-interlaced, 1 for interlaced */
-   png_uint_32 valid; /* the PNG_INFO_ defines, OR'd together */
    /* the following is informational only on read, and not used on
       writes */
    png_byte channels; /* number of channels of data per pixel */
    png_byte pixel_depth; /* number of bits per pixel */
+   png_byte spare_byte;  /* To align the data, and for future use */
 
-   png_uint_32 rowbytes; /* bytes needed for untransformed row */
    /* the rest are optional.  If you are reading, check the valid
       field to see if the information in these are valid.  If you
       are writing, set the valid field to those chunks you want
@@ -184,9 +183,38 @@ typedef struct png_info_struct
 #if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_WRITE_gAMA_SUPPORTED)
    float gamma; /* gamma value of file, if gAMA chunk is valid */
 #endif
+#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_WRITE_tEXt_SUPPORTED) || \
+    defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
+   int num_text; /* number of comments */
+   int max_text; /* size of text array */
+   png_textp text; /* array of comments */
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED) || defined(PNG_WRITE_tIME_SUPPORTED)
+   png_time mod_time; /* modification time */
+#endif
 #if defined(PNG_READ_sBIT_SUPPORTED) || defined(PNG_WRITE_sBIT_SUPPORTED)
    png_color_8 sig_bit; /* significant bits */
 #endif
+#if defined(PNG_READ_tRNS_SUPPORTED) || defined(PNG_WRITE_tRNS_SUPPORTED)
+   png_bytep trans; /* tRNS values for palette image */
+   png_color_16 trans_values; /* tRNS values for non-palette image */
+#endif
+#if defined(PNG_READ_bKGD_SUPPORTED) || defined(PNG_WRITE_bKGD_SUPPORTED)
+   png_color_16 background; /* background color of image */
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
+   png_uint_32 x_offset; /* x offset on page */
+   png_uint_32 y_offset; /* y offset on page */
+   png_byte offset_unit_type; /* offset units type */
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED) || defined(PNG_WRITE_pHYs_SUPPORTED)
+   png_uint_32 x_pixels_per_unit; /* x resolution */
+   png_uint_32 y_pixels_per_unit; /* y resolution */
+   png_byte phys_unit_type; /* resolution type */
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED) || defined(PNG_WRITE_hIST_SUPPORTED)
+   png_uint_16p hist; /* histogram of palette usage */
+#endif
 #if defined(PNG_READ_cHRM_SUPPORTED) || defined(PNG_WRITE_cHRM_SUPPORTED)
    float x_white; /* cHRM chunk values */
    float y_white;
@@ -196,39 +224,6 @@ typedef struct png_info_struct
    float y_green;
    float x_blue;
    float y_blue;
-#endif
-   png_colorp palette; /* palette of file */
-   png_uint_16 num_palette; /* number of values in palette */
-   png_uint_16 num_trans; /* number of trans values */
-#if defined(PNG_READ_tRNS_SUPPORTED) || defined(PNG_WRITE_tRNS_SUPPORTED)
-   png_bytep trans; /* tRNS values for palette image */
-   png_color_16 trans_values; /* tRNS values for non-palette image */
-#endif
-#if defined(PNG_READ_bKGD_SUPPORTED) || defined(PNG_WRITE_bKGD_SUPPORTED)
-
-   png_color_16 background; /* background color of image */
-#endif
-#if defined(PNG_READ_hIST_SUPPORTED) || defined(PNG_WRITE_hIST_SUPPORTED)
-   png_uint_16p hist; /* histogram of palette usage */
-#endif
-#if defined(PNG_READ_pHYs_SUPPORTED) || defined(PNG_WRITE_pHYs_SUPPORTED)
-   png_uint_32 x_pixels_per_unit; /* x resolution */
-   png_uint_32 y_pixels_per_unit; /* y resolution */
-   png_byte phys_unit_type; /* resolution type */
-#endif
-#if defined(PNG_READ_oFFs_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
-   png_uint_32 x_offset; /* x offset on page */
-   png_uint_32 y_offset; /* y offset on page */
-   png_byte offset_unit_type; /* offset units type */
-#endif
-#if defined(PNG_READ_tIME_SUPPORTED) || defined(PNG_WRITE_tIME_SUPPORTED)
-   png_time mod_time; /* modification time */
-#endif
-#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_WRITE_tEXt_SUPPORTED) || \
-    defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
-   int num_text; /* number of comments */
-   int max_text; /* size of text array */
-   png_textp text; /* array of comments */
 #endif
 } png_info;
 typedef png_info        FAR *    png_infop;
@@ -236,9 +231,11 @@ typedef png_info        FAR * FAR * png_infopp;
 
 #define PNG_RESOLUTION_UNKNOWN 0
 #define PNG_RESOLUTION_METER   1
+#define PNG_RESOLUTION_LAST    2
 
 #define PNG_OFFSET_PIXEL       0
 #define PNG_OFFSET_MICROMETER  1
+#define PNG_OFFSET_LAST        2
 
 /* these describe the color_type field in png_info */
 
@@ -248,10 +245,10 @@ typedef png_info        FAR * FAR * png_infopp;
 #define PNG_COLOR_MASK_ALPHA   4
 
 /* color types.  Note that not all combinations are legal */
+#define PNG_COLOR_TYPE_GRAY 0
 #define PNG_COLOR_TYPE_PALETTE \
    (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
-#define PNG_COLOR_TYPE_GRAY 0
 #define PNG_COLOR_TYPE_RGB_ALPHA \
    (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
@@ -269,11 +266,6 @@ typedef png_info        FAR * FAR * png_infopp;
 #define PNG_INFO_oFFs 0x0100
 #define PNG_INFO_tIME 0x0200
 
-/* these determine if a function in the info needs to be freed */
-#define PNG_FREE_PALETTE 0x0001
-#define PNG_FREE_HIST 0x0002
-#define PNG_FREE_TRANS 0x0004
-
 /* this is used for the transformation routines, as some of them
    change these values for the row.  It also should enable using
    the routines for other uses. */
@@ -291,14 +283,14 @@ typedef png_row_info    FAR *    png_row_infop;
 typedef png_row_info    FAR * FAR * png_row_infopp;
 
 /* These are the function types for the I/O functions, and the functions which
- * modify the default I/O functions to user I/O functions.  The png_msg_ptr
+ * modify the default I/O functions to user I/O functions.  The png_error_ptr
  * type should match that of user supplied warning and error functions, while
  * the png_rw_ptr type should match that of the user read/write data functions.
  */
 typedef struct png_struct_def png_struct;
 typedef png_struct FAR * png_structp;
 
-typedef void (*png_msg_ptr) PNGARG((png_structp, png_const_charp));
+typedef void (*png_error_ptr) PNGARG((png_structp, png_const_charp));
 typedef void (*png_rw_ptr) PNGARG((png_structp, png_bytep, png_uint_32));
 typedef void (*png_flush_ptr) PNGARG((png_structp));
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
@@ -316,55 +308,28 @@ typedef void (*png_progressive_row_ptr) PNGARG((png_structp, png_bytep,
 struct png_struct_def
 {
    jmp_buf jmpbuf; /* used in png_error */
+
+   png_error_ptr error_fn;    /* Function for printing errors and aborting */
+   png_error_ptr warning_fn;  /* Function for printing warnings */
+   png_voidp error_ptr;       /* user supplied struct for error functions */
+   png_rw_ptr write_data_fn;  /* Function for writing output data */
+   png_rw_ptr read_data_fn;   /* Function for reading input data */
+   png_voidp io_ptr;  /* Pointer to user supplied struct for I/O functions */
+
    png_byte mode; /* used to determine where we are in the png file */
-   png_byte read_mode;
+   png_uint_32 do_free; /* flags indicating if libpng should free memory */
-   png_byte color_type; /* color type of file */
+   png_uint_32 flags;  /* flags indicating various things to libpng */
-   png_byte bit_depth; /* bit depth of file */
+   png_uint_32 transformations; /* which transformations to perform */
-   png_byte interlaced; /* interlace type of file */
+
-   png_byte compession; /* compression type of file */
+   z_stream * zstream; /* pointer to decompression structure (below) */
-   png_byte filter; /* filter type */
+   png_bytep zbuf; /* buffer for zlib */
-   png_byte channels; /* number of channels in file */
+   png_uint_32 zbuf_size; /* size of zbuf */
-   png_byte pixel_depth; /* number of bits per pixel */
-   png_byte usr_bit_depth; /* bit depth of users row */
-   png_byte usr_channels; /* channels at start of write */
-#if defined(PNG_READ_GAMMA_SUPPORTED)
-   png_byte gamma_shift; /* amount of shift for 16 bit gammas */
-#endif
-   png_byte pass; /* current pass (0 - 6) */
-   png_byte row_init; /* 1 if png_read_start_row() has been called */
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_byte background_gamma_type;
-   png_byte background_expand;
-#endif
-   png_byte zlib_finished;
-   png_byte user_palette;
-#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
-   png_byte filler;
-   png_byte filler_loc;
-#endif
-   png_byte zlib_custom_level; /* one if custom compression level */
-   png_byte zlib_custom_method; /* one if custom compression method */
-   png_byte zlib_custom_window_bits; /* one if custom compression window bits */
-   png_byte zlib_custom_mem_level; /* one if custom compression memory level */
-   png_byte zlib_custom_strategy; /* one if custom compression strategy */
-   png_byte do_filter; /* one if filtering, zero if not */
-   png_byte do_custom_filter; /* one if filtering, zero if not */
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-   png_byte have_chunk_header;
-#endif
-   png_uint_16 num_palette; /* number of entries in palette */
-   png_uint_16 num_trans; /* number of transparency values */
    int zlib_level; /* holds zlib compression level */
    int zlib_method; /* holds zlib compression method */
    int zlib_window_bits; /* holds zlib compression window bits */
    int zlib_mem_level; /* holds zlib compression memory level */
    int zlib_strategy; /* holds zlib compression strategy */
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+
-   int process_mode;
-   int cur_palette;
-#endif
-   png_uint_32 transformations; /* which transformations to perform */
-   png_uint_32 crc; /* current crc value */
    png_uint_32 width; /* width of file */
    png_uint_32 height; /* height of file */
    png_uint_32 num_rows; /* number of rows in current pass */
@@ -373,20 +338,87 @@ struct png_struct_def
    png_uint_32 iwidth; /* interlaced width */
    png_uint_32 irowbytes; /* interlaced rowbytes */
    png_uint_32 row_number; /* current row in pass */
+   png_bytep row_buf; /* row buffer */
+   png_bytep prev_row; /* previous row */
+   png_bytep sub_row;  /* place to save row when filtering */
+   png_bytep up_row;   /* place to save row when filtering */
+   png_bytep avg_row;  /* place to save row when filtering */
+   png_bytep paeth_row; /* place to save row when filtering */
+   png_row_info row_info; /* used for transformation routines */
+
    png_uint_32 idat_size; /* current idat size for read */
-   png_uint_32 zbuf_size; /* size of zbuf */
+   png_uint_32 crc; /* current crc value */
-   png_uint_32 do_free; /* flags indicating if libpng should free memory */
+   png_colorp palette; /* files palette */
+   png_uint_16 num_palette; /* number of entries in palette */
+   png_uint_16 num_trans; /* number of transparency values */
+   png_byte interlaced; /* interlace type of file */
+   png_byte pass; /* current pass (0 - 6) */
+   png_byte compression; /* compression type of file */
+   png_byte filter; /* filter type */
+   png_byte do_filter; /* non-zero if row filtering, zero if not */
+   png_byte color_type; /* color type of file */
+   png_byte bit_depth; /* bit depth of file */
+   png_byte usr_bit_depth; /* bit depth of users row */
+   png_byte pixel_depth; /* number of bits per pixel */
+   png_byte channels; /* number of channels in file */
+   png_byte usr_channels; /* channels at start of write */
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+   png_byte filler; /* filler byte to be used for 32-bit frame buffers */
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_byte background_gamma_type;
+   float background_gamma;
+   png_color_16 background; /* background color, gamma corrected for screen */
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   png_color_16 background_1; /* background normalized to gamma 1.0 */
+#endif
+#endif
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
+   png_flush_ptr output_flush_fn;/* Function for flushing output */
    png_uint_32 flush_dist;  /* how many rows apart to flush, 0 for no flush */
    png_uint_32 flush_rows;  /* number of rows written since last flush */
 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   int gamma_shift; /* amount of shift for 16 bit gammas */
+   float gamma; /* file gamma value */
+   float display_gamma; /* display gamma value */
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep gamma_table; /* gamma table for 8 bit depth files */
+   png_bytep gamma_from_1; /* converts from 1.0 to screen */
+   png_bytep gamma_to_1; /* converts from file to 1.0 */
+   png_uint_16pp gamma_16_table; /* gamma table for 16 bit depth files */
+   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
+   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined (PNG_READ_sBIT_SUPPORTED)
+   png_color_8 sig_bit; /* significant bits in file */
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep trans; /* transparency values for paletted files */
+   png_color_16 trans_values; /* transparency values for non-paletted files */
+#endif
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+   png_color_8 shift; /* shift for significant bit tranformation */
+#endif
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_progressive_info_ptr info_fn;
+   png_progressive_row_ptr row_fn;
+   png_progressive_end_ptr end_fn;
+   png_bytep save_buffer_ptr;
+   png_bytep save_buffer;
+   png_bytep current_buffer_ptr;
+   png_bytep current_buffer;
    png_uint_32 push_length;
    png_uint_32 skip_length;
    png_uint_32 save_buffer_size;
    png_uint_32 save_buffer_max;
    png_uint_32 buffer_size;
    png_uint_32 current_buffer_size;
+   int process_mode;
+   int cur_palette;
+   png_byte push_chunk_name[4];
 #if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_READ_zTXt_SUPPORTED)
    png_uint_32 current_text_size;
    png_uint_32 current_text_left;
@@ -401,85 +433,29 @@ struct png_struct_def
    png_uint_16 offset_table_count;
    png_uint_16 offset_table_count_free;
 #endif
-   png_byte push_chunk_name[4];
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
-   png_bytep save_buffer_ptr;
-   png_bytep save_buffer;
-   png_bytep current_buffer_ptr;
-   png_bytep current_buffer;
-#endif
-   png_colorp palette; /* files palette */
 #if defined(PNG_READ_DITHER_SUPPORTED)
    png_bytep palette_lookup; /* lookup table for dithering */
-#endif
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_bytep gamma_table; /* gamma table for 8 bit depth files */
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_bytep gamma_from_1; /* converts from 1.0 to screen */
-   png_bytep gamma_to_1; /* converts from file to 1.0 */
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_bytep trans; /* transparency values for paletted files */
-#endif
-#if defined(PNG_READ_DITHER_SUPPORTED)
    png_bytep dither_index; /* index translation for palette files */
-#endif
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_uint_16pp gamma_16_table; /* gamma table for 16 bit depth files */
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
-   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
-#endif
-#if defined(PNG_READ_DITHER_SUPPORTED)
    png_uint_16p hist; /* histogram */
 #endif
-   png_bytep zbuf; /* buffer for zlib */
-   png_bytep row_buf; /* row buffer */
-   png_bytep prev_row; /* previous row */
-   png_bytep save_row; /* place to save row before filtering */
-   z_stream * zstream; /* pointer to decompression structure (below) */
-#if defined(PNG_READ_GAMMA_SUPPORTED)
-   float gamma; /* file gamma value */
-   float display_gamma; /* display gamma value */
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   float background_gamma;
-#endif
-#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
-   png_color_8 shift; /* shift for significant bit tranformation */
-#endif
-#if defined(PNG_READ_GAMMA_SUPPORTED) || defined (PNG_READ_sBIT_SUPPORTED)
-   png_color_8 sig_bit; /* significant bits in file */
-#endif
-#if defined(PNG_READ_BACKGROUND_SUPPORTED)
-   png_color_16 trans_values; /* transparency values for non-paletted files */
-   png_color_16 background; /* background color, gamma corrected for screen */
-#if defined(PNG_READ_GAMMA_SUPPORTED)
-   png_color_16 background_1; /* background normalized to gamma 1.0 */
-#endif
-#endif
-   png_row_info row_info; /* used for transformation routines */
-   FILE *fp; /* used for default png_read and png_write */
-   png_msg_ptr error_fn;         /* Function for printing errors and aborting */
-   png_msg_ptr warning_fn;       /* Function for printing warnings */
-   png_rw_ptr write_data_fn;     /* Function for writing output data */
-   png_rw_ptr read_data_fn;      /* Function for reading input data */
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
-   png_flush_ptr output_flush_fn;/* Function for flushing output */
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-   png_progressive_info_ptr info_fn;
-   png_progressive_row_ptr row_fn;
-   png_progressive_end_ptr end_fn;
-   png_voidp push_ptr;
-#endif
-   png_voidp io_ptr;  /* Pointer to user supplied struct for I/O functions */
-   png_voidp msg_ptr;  /* Pointer to user supplied struct for message functions */
 };
 
 typedef png_struct      FAR * FAR * png_structpp;
 
+/* flags for png_set_filter() to say which filters to use.  The flags
+   are chosen so that they don't conflict with real filter types, in case they
+   are supplied instead of the #defined constants.
+ */
+#define PNG_NO_FILTERS     0x00
+#define PNG_FILTER_NONE    0x08
+#define PNG_FILTER_SUB     0x10
+#define PNG_FILTER_UP      0x20
+#define PNG_FILTER_AVG     0x40
+#define PNG_FILTER_PAETH   0x80
+#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
+                         PNG_FILTER_AVG | PNG_FILTER_PAETH)
+
 /* Here are the function definitions most commonly used.  This is not
    the place to find out how to use libpng.  See libpng.txt for the
    full explanation, see example.c for the summary.  This just provides
@@ -488,13 +464,31 @@ typedef png_struct      FAR * FAR * png_structpp;
 /* check the first 1 - 8 bytes to see if it is a png file */
 extern int png_check_sig PNGARG((png_bytep sig, int num));
 
-/* initialize png structure for reading, and allocate any memory needed */
+/* allocate and initialize png structure for reading, and any other memory */
+extern png_structp png_create_read_struct PNGARG((png_const_charp user_png_ver,
+   voidp error_ptr, png_error_ptr warn_fn, png_error_ptr error_fn));
+ 
+/* reset the png_struct to read a new image */
+extern void png_reset_read_struct PNGARG((png_structpp png_ptr));
+
+/* initialize png structure for reading, and allocate any other memory (old) */
 extern void png_read_init PNGARG((png_structp png_ptr));
 
-/* initialize png structure for writing, and allocate any memory needed */
+/* allocate and initialize png structure for reading, and any other memory */
+extern png_structp png_create_write_struct
+   PNGARG((png_const_charp user_png_ver, voidp error_ptr,
+   png_error_ptr warn_fn, png_error_ptr error_fn));
+
+/* reset the png_struct to read a new image */
+extern void png_reset_write_struct PNGARG((png_structpp png_ptr));
+
+/* initialize png structure for writing, and allocate any other memory (old) */
 extern void png_write_init PNGARG((png_structp png_ptr));
 
-/* initialize the info structure */
+/* allocate and initialize the info structure */
+extern png_infop png_create_info_struct PNGARG((png_structp png_ptr));
+
+/* initialize the info structure (old interface) */
 extern void png_info_init PNGARG((png_infop info));
 
 /* Writes all the png information before the image. */
@@ -506,7 +500,7 @@ extern void png_read_info PNGARG((png_structp png_ptr, png_infop info));
 #if defined(PNG_WRITE_tIME_SUPPORTED)
 /* convert from a struct tm to png_time */
 extern void png_convert_from_struct_tm PNGARG((png_timep ptime,
-   struct tm FAR * ttime)); /*SJT: struct tm FAR *tttime ??? */
+   struct tm FAR * ttime));
 
 /* convert from time_t to png_time.  Uses gmtime() */
 extern void png_convert_from_time_t PNGARG((png_timep ptime, time_t ttime));
@@ -533,7 +527,7 @@ extern void png_set_gray_to_rgb PNGARG((png_structp png_ptr));
 #define PNG_FILLER_AFTER 1
 /* Add a filler byte to rgb images. */
 extern void png_set_filler PNGARG((png_structp png_ptr, int filler,
-   int filler_loc));
+   int flags));
 
 /* old ways of doing this, still supported through 1.x for backwards
    compatability, but not suggested */
@@ -574,10 +568,10 @@ extern void png_set_invert_mono PNGARG((png_structp png_ptr));
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
 /* Handle alpha and tRNS by replacing with a background color. */
-#define PNG_BACKGROUND_GAMMA_SCREEN 0
+#define PNG_BACKGROUND_GAMMA_UNKNOWN 0
-#define PNG_BACKGROUND_GAMMA_FILE 1
+#define PNG_BACKGROUND_GAMMA_SCREEN  1
-#define PNG_BACKGROUND_GAMMA_UNIQUE 2
+#define PNG_BACKGROUND_GAMMA_FILE    2
-#define PNG_BACKGROUND_GAMMA_UNKNOWN 3
+#define PNG_BACKGROUND_GAMMA_UNIQUE  3
 extern void png_set_background PNGARG((png_structp png_ptr,
    png_color_16p background_color, int background_gamma_code,
    int need_expand, double background_gamma));
@@ -653,10 +647,22 @@ extern void png_write_end PNGARG((png_structp png_ptr, png_infop info));
 /* read the end of the png file. */
 extern void png_read_end PNGARG((png_structp png_ptr, png_infop info));
 
-/* free all memory used by the read */
+/* free the info structure */
+extern void png_destroy_info_struct PNGARG((png_structp png_ptr,
+   png_infopp info_ptr));
+
+/* free any memory associated with the png_struct and the info_structs */
+extern void png_destroy_read_struct PNGARG((png_structpp png_ptr,
+   png_infopp info, png_infopp end_info));
+
+/* free all memory used by the read (old method) */
 extern void png_read_destroy PNGARG((png_structp png_ptr, png_infop info,
    png_infop end_info));
 
+/* free any memory associated with the png_struct and the info_structs */
+extern void png_destroy_write_struct PNGARG((png_structpp png_ptr,
+   png_infopp info));
+
 /* free any memory used in png struct */
 extern void png_write_destroy PNGARG((png_structp png_ptr));
 
@@ -667,7 +673,8 @@ extern void png_write_destroy PNGARG((png_structp png_ptr));
    performance at the expense of compression can modify them.
    See the compression library header file for an explination
    of these functions */
-extern void png_set_filtering PNGARG((png_structp png_ptr, int filter));
+extern void png_set_filter PNGARG((png_structp png_ptr, int method,
+   int filters));
 
 extern void png_set_compression_level PNGARG((png_structp png_ptr,
    int level));
@@ -684,10 +691,12 @@ extern void png_set_compression_window_bits PNGARG((png_structp png_ptr,
 extern void png_set_compression_method PNGARG((png_structp png_ptr,
    int method));
 
-/* These next functions are stubs of typical c functions for input/output,
+/* These next functions are called for input/output, memory, and error
-   memory, and error handling.  They are in the file pngio.c, and pngerror.c.
+   handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
-   These functions can be replaced at run time for those applications that
+   and call standard C I/O routines such as fread(), fwrite(), and
-   need to handle I/O in a different manner.  See the file libpng.txt for
+   fprintf().  These functions can be made to use other I/O routines
+   at run time for those applications that need to handle I/O in a
+   different manner by calling png_set_???_fn().  See libpng.txt for
    more information */
 
 /* Write the data to whatever output you are using. */
@@ -707,11 +716,11 @@ extern void png_init_io PNGARG((png_structp png_ptr, FILE *fp));
    still do a longjmp to the last setjmp location if you are using this
    method of error handling.  If error_fn or warning_fn is NULL, the
    default functions will be used. */
-extern void png_set_message_fn PNGARG((png_structp png_ptr, png_voidp msg_ptr,
+extern void png_set_error_fn PNGARG((png_structp png_ptr, png_voidp error_ptr,
-   png_msg_ptr error_fn, png_msg_ptr warning_fn));
+   png_error_ptr error_fn, png_error_ptr warning_fn));
 
-/* Return the user pointer associated with the message functions */
+/* Return the user pointer associated with the error functions */
-extern png_voidp png_get_msg_ptr PNGARG((png_structp png_ptr));
+extern png_voidp png_get_error_ptr PNGARG((png_structp png_ptr));
 
 /* Replace the default data output functions with a user supplied one(s).
    If buffered output is not used, then output_flush_fn can be set to NULL.
@@ -753,6 +762,12 @@ extern void * png_realloc PNGARG((png_structp png_ptr, void * ptr,
 /* free's a pointer allocated by png_malloc() */
 extern void png_free PNGARG((png_structp png_ptr, void * ptr));
 
+/* allocate memory for an internal libpng struct */
+extern voidp png_create_struct PNGARG((uInt type));
+
+/* free memory from internal libpng struct */
+extern void png_destroy_struct PNGARG((voidp struct_ptr));
+
 /* Fatal error in libpng - can't continue */ 
 extern void png_error PNGARG((png_structp png_ptr, png_const_charp error));
 
@@ -767,17 +782,17 @@ extern void png_warning PNGARG((png_structp png_ptr, png_const_charp message));
    define PNG_INTERNAL inside your code, so everyone who includes png.h
    won't get yet another definition the compiler has to deal with. */
 
-#ifdef PNG_INTERNAL
+#if defined(PNG_INTERNAL)
 
 /* various modes of operation.  Note that after an init, mode is set to
    zero automatically */
-#define PNG_BEFORE_IHDR 0
+#define PNG_BEFORE_IHDR  0x00
-#define PNG_HAVE_IHDR 1
+#define PNG_HAVE_IHDR    0x01
-#define PNG_HAVE_PLTE 2
+#define PNG_HAVE_PLTE    0x02
-#define PNG_HAVE_IDAT 3
+#define PNG_HAVE_IDAT    0x04
-#define PNG_AT_LAST_IDAT 4
+#define PNG_AT_LAST_IDAT 0x08
-#define PNG_AFTER_IDAT 5
+#define PNG_AFTER_IDAT   0x10
-#define PNG_AFTER_IEND 6
+#define PNG_AFTER_IEND   0x20
 
 /* push model modes */
 #define PNG_READ_SIG_MODE   0
@@ -804,13 +819,37 @@ extern void png_warning PNGARG((png_structp png_ptr, png_const_charp message));
 #define PNG_INVERT_MONO        0x0020
 #define PNG_DITHER             0x0040
 #define PNG_BACKGROUND         0x0080
-#define PNG_XRGB 0x0100
+#define PNG_BACKGROUND_EXPAND  0x0100
-#define PNG_16_TO_8 0x0200
+#define PNG_XRGB               0x0200
-#define PNG_RGBA 0x0400
+#define PNG_16_TO_8            0x0400
-#define PNG_EXPAND 0x0800
+#define PNG_RGBA               0x0800
-#define PNG_GAMMA 0x1000
+#define PNG_EXPAND             0x1000
-#define PNG_GRAY_TO_RGB 0x2000
+#define PNG_GAMMA              0x2000
-#define PNG_FILLER 0x4000
+#define PNG_GRAY_TO_RGB        0x4000
+#define PNG_FILLER             0x8000
+
+/* flags for png_ptr->do_free to say if memory in png_info needs to be freed */
+#define PNG_FREE_PALETTE 0x0001
+#define PNG_FREE_HIST    0x0002
+#define PNG_FREE_TRANS   0x0004
+#define PNG_FREE_STRUCT  0x0008
+#define PNG_FREE_INFO    0x0010
+
+/* flags for png_create_struct */
+#define PNG_STRUCT_PNG   0x0001
+#define PNG_STRUCT_INFO  0x0002
+
+/* flags for the png_ptr->flags rather than declaring a bye for each one */
+#define PNG_FLAG_WROTE_tIME               0x0001
+#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0002
+#define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0004
+#define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0008
+#define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0010
+#define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0020
+#define PNG_FLAG_ZLIB_FINISHED            0x0040
+#define PNG_FLAG_ROW_INIT                 0x0080
+#define PNG_FLAG_FILLER_AFTER             0x0100
+#define PNG_FLAG_HAVE_CHUNK_HEADER        0x0200
 
 /* save typing and make code easier to understand */
 #define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
@@ -826,44 +865,24 @@ extern png_byte png_sig[];
 extern char png_libpng_ver[];
 
 /* constant strings for known chunk types.  If you need to add a chunk,
-   add a string holding the name here.  See png.c for more details */
+   add a string holding the name here.  See png.c for more details.  We
+   can't selectively include these, since we still check for chunk in the
+   wrong locations with these labels. */
 extern png_byte FARDATA png_IHDR[];
 extern png_byte FARDATA png_IDAT[];
 extern png_byte FARDATA png_IEND[];
 extern png_byte FARDATA png_PLTE[];
-#if defined(PNG_READ_gAMA_SUPPORTED) || defined(PNG_WRITE_gAMA_SUPPORTED)
 extern png_byte FARDATA png_gAMA[];
-#endif
-#if defined(PNG_READ_sBIT_SUPPORTED) || defined(PNG_WRITE_sBIT_SUPPORTED)
 extern png_byte FARDATA png_sBIT[];
-#endif
-#if defined(PNG_READ_cHRM_SUPPORTED) || defined(PNG_WRITE_cHRM_SUPPORTED)
 extern png_byte FARDATA png_cHRM[];
-#endif
-#if defined(PNG_READ_tRNS_SUPPORTED) || defined(PNG_WRITE_tRNS_SUPPORTED)
 extern png_byte FARDATA png_tRNS[];
-#endif
-#if defined(PNG_READ_bKGD_SUPPORTED) || defined(PNG_WRITE_bKGD_SUPPORTED)
 extern png_byte FARDATA png_bKGD[];
-#endif
-#if defined(PNG_READ_hIST_SUPPORTED) || defined(PNG_WRITE_hIST_SUPPORTED)
 extern png_byte FARDATA png_hIST[];
-#endif
-#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_WRITE_tEXt_SUPPORTED)
 extern png_byte FARDATA png_tEXt[];
-#endif
-#if defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
 extern png_byte FARDATA png_zTXt[];
-#endif
-#if defined(PNG_READ_pHYs_SUPPORTED) || defined(PNG_WRITE_pHYs_SUPPORTED)
 extern png_byte FARDATA png_pHYs[];
-#endif
-#if defined(PNG_READ_oFFs_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)
 extern png_byte FARDATA png_oFFs[];
-#endif
-#if defined(PNG_READ_tIME_SUPPORTED) || defined(PNG_WRITE_tIME_SUPPORTED)
 extern png_byte FARDATA png_tIME[];
-#endif
 /* Structures to facilitate easy interlacing.  See png.c for more details */
 extern int FARDATA png_pass_start[];
 extern int FARDATA png_pass_inc[];
@@ -894,14 +913,8 @@ extern void png_reset_crc PNGARG((png_structp png_ptr));
 extern void png_calculate_crc PNGARG((png_structp png_ptr, png_bytep ptr,
    png_uint_32 length));
 
-/* default error and warning functions if user doesn't supply them */
-extern void png_default_warning PNGARG((png_structp png_ptr,
-   png_const_charp message));
-extern void png_default_error PNGARG((png_structp png_ptr,
-   png_const_charp error));
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
 extern void png_flush PNGARG((png_structp png_ptr));
-extern void png_default_flush PNGARG((png_structp png_ptr));
 #endif
 
 /* place a 32 bit number into a buffer in png byte order.  We work
@@ -1105,11 +1118,14 @@ extern void png_do_write_interlace PNGARG((png_row_infop row_info,
 #endif
 
 /* unfilter a row */
-extern void png_read_filter_row PNGARG((png_row_infop row_info,
+extern void png_read_filter_row PNGARG((png_structp png_ptr,
-   png_bytep row, png_bytep prev_row, int filter));
+   png_row_infop row_info, png_bytep row, png_bytep prev_row, int filter));
-/* filter a row, and place the correct filter byte in the row */
+/* choose the best filter to use and filter the row data */
-extern void png_write_filter_row PNGARG((png_row_infop row_info,
+extern void png_write_find_filter PNGARG((png_structp png_ptr,
-   png_bytep row, png_bytep prev_row));
+   png_row_infop row_info));
+/* write out the filtered row */
+extern void png_write_filtered_row PNGARG((png_structp png_ptr,
+   png_bytep filtered_row));
 /* finish a row while reading, dealing with interlacing passes, etc. */
 extern void png_read_finish_row PNGARG((png_structp png_ptr));
 /* initialize the row buffers, etc. */
@@ -1163,6 +1179,11 @@ extern void png_do_dither PNGARG((png_row_infop row_info,
    png_bytep row, png_bytep palette_lookup, png_bytep dither_lookup));
 #endif
 
+#if defined(PNG_CORRECT_PALETTE_SUPPORTED)
+extern void png_correct_palette PNGARG((png_structp png_ptr,
+   png_colorp palette, int num_palette));
+#endif
+
 #if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
 extern void png_do_bgr PNGARG((png_row_infop row_info, png_bytep row));
 #endif
@@ -1289,13 +1310,13 @@ extern void png_push_fill_buffer PNGARG((png_structp png_ptr, png_bytep buffer,
 extern void png_push_save_buffer PNGARG((png_structp png_ptr));
 extern void png_push_restore_buffer PNGARG((png_structp png_ptr, png_bytep buffer,
    png_uint_32 buffer_length));
-extern void png_push_read_idat PNGARG((png_structp png_ptr));
+extern void png_push_read_IDAT PNGARG((png_structp png_ptr));
 extern void png_process_IDAT_data PNGARG((png_structp png_ptr,
    png_bytep buffer, png_uint_32 buffer_length));
 extern void png_push_process_row PNGARG((png_structp png_ptr));
 extern void png_push_handle_PLTE PNGARG((png_structp png_ptr,
    png_uint_32 length));
-extern void png_push_read_plte PNGARG((png_structp png_ptr, png_infop info));
+extern void png_push_read_PLTE PNGARG((png_structp png_ptr, png_infop info));
 extern void png_push_handle_tRNS PNGARG((png_structp png_ptr, png_infop info,
    png_uint_32 length));
 extern void png_push_handle_hIST PNGARG((png_structp png_ptr, png_infop info,
@@ -1310,12 +1331,12 @@ extern void png_read_push_finish_row PNGARG((png_structp png_ptr));
 #if defined(PNG_READ_tEXt_SUPPORTED)
 extern void png_push_handle_tEXt PNGARG((png_structp png_ptr,
    png_uint_32 length));
-extern void png_push_read_text PNGARG((png_structp png_ptr, png_infop info));
+extern void png_push_read_tEXt PNGARG((png_structp png_ptr, png_infop info));
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
 extern void png_push_handle_zTXt PNGARG((png_structp png_ptr,
    png_uint_32 length));
-extern void png_push_read_ztxt PNGARG((png_structp png_ptr, png_infop info));
+extern void png_push_read_zTXt PNGARG((png_structp png_ptr, png_infop info));
 #endif
 
 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

pngchang.txt

@@ -74,3 +74,30 @@ version 0.88
    fixed progressive bugs
    replaced tabs with spaces
    cleaned up documentation
+   added callbacks for read/write and warning/error functions
+version 0.89 
+   added new initialization API to make libpng work better with shared libs
+      we now have png_create_read_struct(), png_create_write_struct(),
+      png_create_info_struct(), png_destroy_read_struct(), and
+      png_destroy_write_struct() instead of the separate calls to
+      malloc and png_read_init(), png_info_init(), and png_write_init()
+   changed warning/error callback functions to fix bug - this means you
+      should use the new initialization API if you were using the old
+      png_set_message_fn() calls, and that the old API no longer exists
+      so that people are aware that they need to change their code
+   changed filter selection API to allow selection of multiple filters
+      since it didn't work in previous versions of libpng anyways
+   optimized filter selection code    
+   fixed png_set_background() to allow using an arbitrary RGB color for
+      paletted images
+   fixed gamma and background correction for paletted images, so
+      png_correct_palette is not needed unless you are correcting an
+      external palette (you will need to #define PNG_CORRECT_PALETTE_SUPPORTED
+      in pngconf.h)
+   fixed bug with Borland 64K memory allocation (Alexander Lehmann)
+   fixed bug in interlace handling (Smaraderagd, I think)
+   added more error checking for writing and image to reduce invalid files
+   separated read and write functions so that they won't both be linked
+      into a binary when only reading or writing functionality is used
+   new pngtest image also has interlacing and zTXt
+   updated dcumentation to reflect new API

pngconf.h

@@ -1,10 +1,10 @@
 
 /* pngconf.c - machine configurable file for libpng
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 /* Any machine specific code is near the front of this file, so if you
@@ -78,7 +78,7 @@
 #endif /* PNGARG */
 
 /* enough people need this for various reasons to include it here */
-#ifndef MACOS
+#if !defined(MACOS) && !defined(RISCOS)
 #include <sys/types.h>
 #endif
 /* need the time information for reading tIME chunks */
@@ -179,6 +179,7 @@
 #define PNG_READ_FILLER_SUPPORTED
 #define PNG_READ_GAMMA_SUPPORTED
 #define PNG_READ_GRAY_TO_RGB_SUPPORTED
+#undef  PNG_CORRECT_PALETTE_SUPPORTED
 
 #define PNG_WRITE_INTERLACING_SUPPORTED
 #define PNG_WRITE_SHIFT_SUPPORTED

pngerror.c

@@ -1,22 +1,27 @@
 
 /* pngerror.c - stub functions for i/o and memory allocation
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
 
    This file provides a location for all error handling.  Users which
    need special error handling are expected to write replacement functions
-   and use png_set_message_fn() to use those functions.  See the instructions
+   and use png_set_error_fn() to use those functions.  See the instructions
    at each function. */
 
 #define PNG_INTERNAL
 #include "png.h"
 
+static void png_default_error PNGARG((png_structp png_ptr,
+                                      png_const_charp message));
+static void png_default_warning PNGARG((png_structp png_ptr,
+                                        png_const_charp message));
+
 /* This function is called whenever there is a fatal error.  This function
    should not be changed.  If there is a need to handle errors differently,
-   you should supply a replacement error function and use png_set_message_fn()
+   you should supply a replacement error function and use png_set_error_fn()
    to replace the error function at run-time. */
 void
 png_error(png_structp png_ptr, png_const_charp message)
@@ -32,7 +37,7 @@ png_error(png_structp png_ptr, png_const_charp message)
 /* This function is called whenever there is a non-fatal error.  This function
    should not be changed.  If there is a need to handle warnings differently,
    you should supply a replacement warning function and use
-   png_set_message_fn() to replace the warning function at run-time. */
+   png_set_error_fn() to replace the warning function at run-time. */
 void
 png_warning(png_structp png_ptr, png_const_charp message)
 {
@@ -45,8 +50,8 @@ png_warning(png_structp png_ptr, png_const_charp message)
 /* This is the default error handling function.  Note that replacements for
    this function MUST NOT RETURN, or the program will likely crash.  This
    function is used by default, or if the program supplies NULL for the
-   error function pointer in png_set_message_fn(). */
+   error function pointer in png_set_error_fn(). */
-void
+static void
 png_default_error(png_structp png_ptr, png_const_charp message)
 {
 #ifndef PNG_NO_STDIO
@@ -68,7 +73,7 @@ png_default_error(png_structp png_ptr, png_const_charp message)
    it can continue anyway.  Replacement functions don't have to do anything
    here if you don't want to.  In the default configuration, png_ptr is
    not used, but it is passed in case it may be useful. */
-void
+static void
 png_default_warning(png_structp png_ptr, png_const_charp message)
 {
    if (!png_ptr)
@@ -81,27 +86,25 @@ png_default_warning(png_structp png_ptr, png_const_charp message)
 
 /* This function is called when the application wants to use another method
    of handling errors and warnings.  Note that the error function MUST NOT
-   return to the calling routine or serious problems will occur. The error
+   return to the calling routine or serious problems will occur.  The return
-   return method used in the default routine calls
+   method used in the default routine calls longjmp(png_ptr->jmpbuf, 1) */
-   longjmp(png_ptr->jmpbuf, 1) */
 void
-png_set_message_fn(png_structp png_ptr, png_voidp msg_ptr, png_msg_ptr error_fn,
+png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
-   png_msg_ptr warning_fn)
+   png_error_ptr error_fn, png_error_ptr warning_fn)
 {
-   png_ptr->msg_ptr = msg_ptr;
+   png_ptr->error_ptr = error_ptr;
-
    png_ptr->error_fn = error_fn;
    png_ptr->warning_fn = warning_fn;
 }
 
 
-/* This function returns a pointer to the msg_ptr associated with the user
+/* This function returns a pointer to the error_ptr associated with the user
    functions.  The application should free any memory associated with this
    pointer before png_write_destroy and png_read_destroy are called. */
 png_voidp
-png_get_msg_ptr(png_structp png_ptr)
+png_get_error_ptr(png_structp png_ptr)
 {
-   return png_ptr->msg_ptr;
+   return png_ptr->error_ptr;
 }
 
 

pngio.c

@@ -1,318 +0,0 @@
-
-/* pngio.c - stub functions for i/o and memory allocation
-
-   libpng 1.0 beta 2 - version 0.88
-   For conditions of distribution and use, see copyright notice in png.h
-   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
-
-   This file provides a location for all input/output.  Users which need
-   special handling are expected to write functions which have the same
-   arguments as these, and perform similar functions, but possibly have
-   different I/O methods.  Note that you shouldn't change these functions,
-   but rather write replacement functions and then change them at run
-   time with png_set_write_fn(...) or png_set_read_fn(...), etc */
-
-#define PNG_INTERNAL
-#include "png.h"
-
-/* Write the data to whatever output you are using.  The default routine
-   writes to a file pointer.  Note that this routine sometimes gets called
-   with very small lengths, so you should implement some kind of simple
-   buffering if you are using unbuffered writes.  This should never be asked
-   to write more then 64K on a 16 bit machine.  The cast to png_size_t is
-   there to quiet warnings of certain compilers. */
-
-void
-png_write_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
-{
-   if (png_ptr->write_data_fn)
-      (*(png_ptr->write_data_fn))(png_ptr, data, length);
-   else
-      png_error(png_ptr, "Call to NULL write function");
-}
-
-/* This is the function which does the actual writing of data.  If you are
-   not writing to a standard C stream, you should create a replacement
-   write_data function and use it at run time with png_set_write_fn(), rather
-   than changing the library. */
-#ifndef USE_FAR_KEYWORD
-void
-png_default_write_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
-{
-   png_uint_32 check;
-
-   check = fwrite(data, 1, (png_size_t)length, png_ptr->fp);
-   if (check != length)
-   {
-      png_error(png_ptr, "Write Error");
-   }
-}
-#else
-/* this is the model-independent version. Since the standard I/O library
-   can't handle far buffers in the medium and small models, we have to copy
-   the data.
-*/
-
-#define NEAR_BUF_SIZE 1024
-#define MIN(a,b) (a <= b ? a : b)
-
-#ifdef _MSC_VER
-/* for FP_OFF */
-#include <dos.h>
-#endif
-
-void
-png_default_write_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
-{
-   png_uint_32 check;
-   png_byte *n_data;
-
-   /* Check if data really is near. If so, use usual code. */
-#ifdef _MSC_VER
-   /* do it this way just to quiet warning */
-   FP_OFF(n_data) = FP_OFF(data);
-   if (FP_SEG(n_data) == FP_SEG(data))
-#else
-   /* this works in MSC also but with lost segment warning */
-   n_data = (png_byte *)data;
-   if ((png_bytep)n_data == data)
-#endif
-   {
-      check = fwrite(n_data, 1, (png_size_t)length, png_ptr->fp);
-   }
-   else
-   {
-      png_byte buf[NEAR_BUF_SIZE];
-      png_size_t written, remaining, err;
-      check = 0;
-      remaining = (png_size_t)length;
-      do
-      {
-         written = MIN(NEAR_BUF_SIZE, remaining);
-         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
-         err = fwrite(buf, 1, written, png_ptr->fp);
-         if (err != written)
-            break;
-         else
-            check += err;
-         data += written;
-         remaining -= written;
-      }
-      while (remaining != 0);
-   }
-   if (check != length)
-   {
-      png_error(png_ptr, "Write Error");
-   }
-}
-
-#endif
-
-/* Read the data from whatever input you are using.  The default routine
-   reads from a file pointer.  Note that this routine sometimes gets called
-   with very small lengths, so you should implement some kind of simple
-   buffering if you are using unbuffered reads.  This should never be asked
-   to read more then 64K on a 16 bit machine.  The cast to png_size_t is
-   there to quiet some compilers */
-void
-png_read_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
-{
-#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
-   if (png_ptr->read_mode == PNG_READ_PUSH_MODE)
-   {
-      png_push_fill_buffer(png_ptr, data, length);
-   }
-   else
-#endif
-   {
-      if (png_ptr->read_data_fn)
-         (*(png_ptr->read_data_fn))(png_ptr, data, length);
-      else
-         png_error(png_ptr, "Call to NULL read function");
-   }
-}
-
-/* This is the function which does the actual reading of data.  If you are
-   not reading from a standard C stream, you should create a replacement
-   read_data function and use it at run time with png_set_read_fn(), rather
-   than changing the library. */
-#ifndef USE_FAR_KEYWORD
-void
-png_default_read_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
-{
-   png_uint_32 check;
-
-   check = fread(data, 1, (size_t)length, png_ptr->fp);
-   if (check != length)
-   {
-      png_error(png_ptr, "Read Error");
-   }
-}
-#else
-void
-png_default_read_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
-{
-   png_uint_32 check;
-   png_byte *n_data;
-
-   /* Check if data really is near. If so, use usual code. */
-#ifdef _MSC_VER
-   /* do it this way just to quiet warning */
-   FP_OFF(n_data) = FP_OFF(data);
-   if (FP_SEG(n_data) == FP_SEG(data))
-#else
-   /* this works in MSC also but with lost segment warning */
-   n_data = (png_byte *)data;
-   if ((png_bytep)n_data == data)
-#endif
-   {
-      check = fread(n_data, 1, (size_t)length, png_ptr->fp);
-   }
-   else
-   {
-      png_byte buf[NEAR_BUF_SIZE];
-      png_size_t read, remaining, err;
-      check = 0;
-      remaining = (png_size_t)length;
-      do
-      {
-         read = MIN(NEAR_BUF_SIZE, remaining);
-         err = fread(buf, 1, read, png_ptr->fp);
-         png_memcpy(data, buf, read); /* copy far buffer to near buffer */
-         if(err != read)
-            break;
-         else
-            check += err;
-         data += read;
-         remaining -= read;
-      }
-      while (remaining != 0);
-   }
-   if (check != length)
-   {
-      png_error(png_ptr, "read Error");
-   }
-}
-#endif
-
-/* This function is called to output any data pending writing (normally
-   to disk.  After png_flush is called, there should be no data pending
-   writing in any buffers. */
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
-void
-png_flush(png_structp png_ptr)
-{
-   if (png_ptr->output_flush_fn)
-      (*(png_ptr->output_flush_fn))(png_ptr);
-}
-
-void
-png_default_flush(png_structp png_ptr)
-{
-   if (png_ptr->fp)
-      fflush(png_ptr->fp);
-}
-#endif
-
-/* This function allows the application to supply new output functions for
-   libpng if standard C streams aren't being used.
-
-   This function takes as its arguments:
-   png_ptr       - pointer to a png output data structure
-   io_ptr        - pointer to user supplied structure containing info about
-                   the output functions.  May be NULL.
-   write_data_fn - pointer to a new output function which takes as its
-                   arguments a pointer to a png_struct, a pointer to
-                   data to be written, and a 32-bit unsigned int which is
-                   the number of bytes to be written.  The new write
-                   function should call png_error(png_ptr, "Error msg")
-                   to exit and output any fatal error messages.
-   flush_data_fn - pointer to a new flush function which takes as its
-                   arguments a pointer to a png_struct.  After a call to
-                   the flush function, there should be no data in any buffers
-                   or pending transmission.  If the output method doesn't do
-                   any buffering of ouput, a function prototype must still be
-                   supplied although it doesn't have to do anything.  If
-                   PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
-                   time, output_flush_fn will be ignored, although it must be
-                   supplied for compatibility. */
-void
-png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
-   png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
-{
-   png_ptr->io_ptr = io_ptr;
-
-   if (write_data_fn)
-      png_ptr->write_data_fn = write_data_fn;
-   else
-      png_ptr->write_data_fn = png_default_write_data;
-
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
-   if (output_flush_fn)
-      png_ptr->output_flush_fn = output_flush_fn;
-   else
-      png_ptr->output_flush_fn = png_default_flush;
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
-
-   /* It is an error to read while writing a png file */
-   png_ptr->read_data_fn = NULL;
-}
-
-
-/* This function allows the application to supply a new input function
-   for libpng if standard C streams aren't being used.
-
-   This function takes as its arguments:
-   png_ptr      - pointer to a png input data structure
-   io_ptr       - pointer to user supplied structure containing info about
-                  the input functions.  May be NULL.
-   read_data_fn - pointer to a new input function which takes as it's
-                  arguments a pointer to a png_struct, a pointer to
-                  a location where input data can be stored, and a 32-bit
-                  unsigned int which is the number of bytes to be read.
-                  To exit and output any fatal error messages the new write
-                  function should call png_error(png_ptr, "Error msg"). */
-void
-png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
-   png_rw_ptr read_data_fn)
-{
-   png_ptr->io_ptr = io_ptr;
-
-   if (read_data_fn)
-      png_ptr->read_data_fn = read_data_fn;
-   else
-      png_ptr->read_data_fn = png_default_read_data;
-
-   /* It is an error to write to a read device */
-   png_ptr->write_data_fn = NULL;
-
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
-   png_ptr->output_flush_fn = NULL;
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
-}
-
-
-/* This function returns a pointer to the io_ptr associated with the user
-   functions.  The application should free any memory associated with this
-   pointer before png_write_destroy and png_read_destroy are called. */
-png_voidp
-png_get_io_ptr(png_structp png_ptr)
-{
-   return png_ptr->io_ptr;
-}
-
-/* Initialize the default input/output functions for the png file.  If you
-   change the read, or write routines, you can call either png_set_read_fn()
-   or png_set_write_fn() instead of png_init_io(). */
-void
-png_init_io(png_structp png_ptr, FILE *fp)
-{
-   png_ptr->fp = fp;
-   png_ptr->read_data_fn = png_default_read_data;
-   png_ptr->write_data_fn = png_default_write_data;
-#ifdef PNG_WRITE_FLUSH_SUPPORTED
-   png_ptr->output_flush_fn = png_default_flush;
-#endif
-}
-

pngmem.c

@@ -1,10 +1,10 @@
 
 /* pngmem.c - stub functions for memory allocation
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
 
    This file provides a location for all memory allocation.  Users which
    need special memory handling are expected to modify the code in this file
@@ -17,6 +17,39 @@
 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
 /* if you change this, be sure to change the one in png.h also */
 
+/* Allocate memory for a png_struct.  The malloc and memset can be replaced
+ * by a single call to calloc() if this is thought to improve performance.
+ */
+png_voidp
+png_create_struct(uInt type)
+{
+   png_size_t type;
+   png_voidp struct_ptr;
+
+   if (type == PNG_STRUCT_INFO)
+     size = sizeof(png_info);
+   else if (type == PNG_STRUCT_PNG)
+     size = sizeof(png_struct);
+   else
+     return (png_voidp)NULL;
+
+   if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
+   {
+      png_memset(struct_ptr, 0, size);
+   }
+
+   return (struct_ptr);
+}
+
+
+/* Free memory allocated by a png_create_struct() call */
+void
+png_destroy_struct(png_voidp struct_ptr)
+{
+   if (struct_ptr)
+      farfree (struct_ptr);
+}
+
 /* Allocate memory.  For reasonable files, size should never exceed
    64K.  However, zlib may allocate more then 64K if you don't tell
    it not to.  See zconf.h and png.h for more information. zlib does
@@ -27,7 +60,9 @@
    It gives you a segment with an offset of 8 (perhaps to store it's
    memory stuff).  zlib doesn't like this at all, so we have to
    detect and deal with it.  This code should not be needed in
-   Windows or OS/2 modes, and only in 16 bit mode.
+   Windows or OS/2 modes, and only in 16 bit mode.  This code has
+   been updated by Alexander Lehmann for version 0.89 to waste less
+   memory.
 */
 
 png_voidp
@@ -35,7 +70,7 @@ png_large_malloc(png_structp png_ptr, png_uint_32 size)
 {
    png_voidp ret;
    if (!png_ptr || !size)
-      return ((voidp)0);
+      return ((voidp)NULL);
 
 #ifdef PNG_MAX_MALLOC_64K
    if (size > (png_uint_32)65536L)
@@ -58,7 +93,7 @@ png_large_malloc(png_structp png_ptr, png_uint_32 size)
 
             if (ret)
                farfree(ret);
-            ret = 0;
+            ret = NULL;
 
             num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
             if (num_blocks < 1)
@@ -68,7 +103,7 @@ png_large_malloc(png_structp png_ptr, png_uint_32 size)
             else
                num_blocks++;
 
-            total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks;
+            total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
 
             table = farmalloc(total_size);
 
@@ -77,27 +112,25 @@ png_large_malloc(png_structp png_ptr, png_uint_32 size)
                png_error(png_ptr, "Out of Memory");
             }
 
-            if ((long)table & 0xffff)
+            if ((long)table & 0xfff0)
             {
-               farfree(table);
+               png_error(png_ptr, "Farmalloc didn't return normalized pointer");
-               total_size += (png_uint_32)65536L;
-            }
-
-            table = farmalloc(total_size);
-
-            if (!table)
-            {
-               png_error(png_ptr, "Out of Memory");
             }
 
             png_ptr->offset_table = table;
             png_ptr->offset_table_ptr = farmalloc(
                num_blocks * sizeof (png_bytep));
-            hptr = (png_byte huge *)table;
+
-            if ((long)hptr & 0xffff)
+            if (!png_ptr->offset_table_ptr)
             {
-               hptr = (png_byte huge *)((long)(hptr) & 0xffff0000L);
+               png_error(png_ptr, "Out of memory");
-               hptr += 65536L;
+            }
+
+            hptr = (png_byte huge *)table;
+            if ((long)hptr & 0xf)
+            {
+               hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
+               hptr += 16L;
             }
             for (i = 0; i < num_blocks; i++)
             {
@@ -109,13 +142,13 @@ png_large_malloc(png_structp png_ptr, png_uint_32 size)
             png_ptr->offset_table_count = 0;
             png_ptr->offset_table_count_free = 0;
          }
+      }
 
       if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
          png_error(png_ptr, "Out of Memory");
 
       ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
    }
-   }
    else
       ret = farmalloc(size);
 
@@ -167,13 +200,63 @@ png_large_free(png_structp png_ptr, png_voidp ptr)
 
 #else /* Not the Borland DOS special memory handler */
 
+/* Allocate memory for a png_struct or a png_info.  The malloc and
+ * memset can be replaced by a single call to calloc() if this is thought
+ * to improve performance noticably.
+ */
+png_voidp
+png_create_struct(uInt type)
+{
+   size_t size;
+   png_voidp struct_ptr;
+
+   if (type == PNG_STRUCT_INFO)
+     size = sizeof(png_info);
+   else if (type == PNG_STRUCT_PNG)
+     size = sizeof(png_struct);
+   else
+     return (png_voidp)NULL;
+
+#if defined(__TURBOC__) && !defined(__FLAT__)
+   if ((struct_ptr = (png_voidp)farmalloc(size)) != NULL)
+#else
+# if defined(_MSC_VER) && defined(MAXSEG_64K)
+   if ((struct_ptr = (png_voidp)halloc(size)) != NULL)
+# else
+   if ((struct_ptr = (png_voidp)malloc(size)) != NULL)
+# endif
+#endif
+   {
+      png_memset(struct_ptr, 0, size);
+   }
+
+   return (struct_ptr);
+}
+
+
+/* Free memory allocated by a png_create_struct() call */
+void
+png_destroy_struct(png_voidp struct_ptr)
+{
+   if (struct_ptr)
+#if defined(__TURBOC__) && !defined(__FLAT__)
+      farfree(struct_ptr);
+#else
+# if defined(_MSC_VER) && defined(MAXSEG_64K)
+      hfree(struct_ptr);
+# else
+      free(struct_ptr);
+# endif
+#endif
+}
+
+
 /* Allocate memory.  For reasonable files, size should never exceed
    64K.  However, zlib may allocate more then 64K if you don't tell
    it not to.  See zconf.h and png.h for more information. zlib does
    need to allocate exactly 64K, so whatever you call here must
    have the ability to do that. */
 
-
 png_voidp
 png_large_malloc(png_structp png_ptr, png_uint_32 size)
 {
@@ -300,4 +383,3 @@ png_free(png_structp png_ptr, void * ptr)
       free(ptr);
 }
 
-

pngpread.c

@@ -1,10 +1,10 @@
 
 /* pngpread.c - read a png file in push mode
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -41,25 +41,25 @@ png_process_some_data(png_structp png_ptr, png_infop info)
       }
       case PNG_READ_IDAT_MODE:
       {
-         png_push_read_idat(png_ptr);
+         png_push_read_IDAT(png_ptr);
          break;
       }
       case PNG_READ_PLTE_MODE:
       {
-         png_push_read_plte(png_ptr, info);
+         png_push_read_PLTE(png_ptr, info);
          break;
       }
 #if defined(PNG_READ_tEXt_SUPPORTED)
       case PNG_READ_tEXt_MODE:
       {
-         png_push_read_text(png_ptr, info);
+         png_push_read_tEXt(png_ptr, info);
          break;
       }
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
       case PNG_READ_zTXt_MODE:
       {
-         png_push_read_ztxt(png_ptr, info);
+         png_push_read_zTXt(png_ptr, info);
          break;
       }
 #endif
@@ -107,7 +107,7 @@ png_push_read_sig(png_structp png_ptr)
 void
 png_push_read_chunk(png_structp png_ptr, png_infop info)
 {
-   if (!png_ptr->have_chunk_header)
+   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_start[8];
 
@@ -120,7 +120,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
       png_push_fill_buffer(png_ptr, chunk_start, 8);
       png_ptr->push_length = png_get_uint_32(chunk_start);
       png_memcpy(png_ptr->push_chunk_name, (png_voidp)(chunk_start + 4), 4);
-      png_ptr->have_chunk_header = 1;
+      png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
       png_reset_crc(png_ptr);
       png_calculate_crc(png_ptr, chunk_start + 4, 4);
    }
@@ -128,7 +128,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
    if (!png_memcmp(png_ptr->push_chunk_name, png_IHDR, 4))
    {
       if (png_ptr->mode != PNG_BEFORE_IHDR)
-         png_error(png_ptr, "Out of Place IHDR");
+         png_error(png_ptr, "Out of place IHDR");
 
       if (png_ptr->push_length + 4 > png_ptr->buffer_size)
       {
@@ -168,7 +168,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
    }
    else if (!png_memcmp(png_ptr->push_chunk_name, png_IEND, 4))
    {
-      png_error(png_ptr, "No Image in File");
+      png_error(png_ptr, "No image in file");
    }
 #if defined(PNG_READ_gAMA_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_gAMA, 4))
@@ -180,7 +180,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
       }
 
       if (png_ptr->mode != PNG_HAVE_IHDR)
-         png_error(png_ptr, "Out of Place gAMA");
+         png_error(png_ptr, "Out of place gAMA");
 
       png_handle_gAMA(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -196,7 +196,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
       }
 
       if (png_ptr->mode != PNG_HAVE_IHDR)
-         png_error(png_ptr, "Out of Place sBIT");
+         png_error(png_ptr, "Out of place sBIT");
 
       png_handle_sBIT(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -212,7 +212,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
       }
 
       if (png_ptr->mode != PNG_HAVE_IHDR)
-         png_error(png_ptr, "Out of Place cHRM");
+         png_error(png_ptr, "Out of place cHRM");
 
       png_handle_cHRM(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -228,7 +228,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
       }
       if (png_ptr->mode != PNG_HAVE_IHDR &&
          png_ptr->mode != PNG_HAVE_PLTE)
-         png_error(png_ptr, "Out of Place tRNS");
+         png_error(png_ptr, "Out of place tRNS");
 
       png_handle_tRNS(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -245,7 +245,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
 
       if (png_ptr->mode != PNG_HAVE_IHDR &&
          png_ptr->mode != PNG_HAVE_PLTE)
-         png_error(png_ptr, "Out of Place bKGD");
+         png_error(png_ptr, "Out of place bKGD");
 
       png_handle_bKGD(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -261,7 +261,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
       }
 
       if (png_ptr->mode != PNG_HAVE_PLTE)
-         png_error(png_ptr, "Out of Place hIST");
+         png_error(png_ptr, "Out of place hIST");
 
       png_handle_hIST(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -278,7 +278,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
 
       if (png_ptr->mode != PNG_HAVE_IHDR &&
          png_ptr->mode != PNG_HAVE_PLTE)
-         png_error(png_ptr, "Out of Place pHYs");
+         png_error(png_ptr, "Out of place pHYs");
 
       png_handle_pHYs(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -295,7 +295,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
 
       if (png_ptr->mode != PNG_HAVE_IHDR &&
          png_ptr->mode != PNG_HAVE_PLTE)
-         png_error(png_ptr, "Out of Place oFFs");
+         png_error(png_ptr, "Out of place oFFs");
 
       png_handle_oFFs(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -312,7 +312,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
 
       if (png_ptr->mode == PNG_BEFORE_IHDR ||
          png_ptr->mode == PNG_AFTER_IEND)
-         png_error(png_ptr, "Out of Place tIME");
+         png_error(png_ptr, "Out of place tIME");
 
       png_handle_tIME(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -323,7 +323,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
    {
       if (png_ptr->mode == PNG_BEFORE_IHDR ||
          png_ptr->mode == PNG_AFTER_IEND)
-         png_error(png_ptr, "Out of Place tEXt");
+         png_error(png_ptr, "Out of place tEXt");
 
       png_push_handle_tEXt(png_ptr, png_ptr->push_length);
    }
@@ -333,19 +333,43 @@ png_push_read_chunk(png_structp png_ptr, png_infop info)
    {
       if (png_ptr->mode == PNG_BEFORE_IHDR ||
          png_ptr->mode == PNG_AFTER_IEND)
-         png_error(png_ptr, "Out of Place zTXt");
+         png_error(png_ptr, "Out of place zTXt");
 
       png_push_handle_zTXt(png_ptr, png_ptr->push_length);
    }
 #endif
    else
    {
+      if (png_ptr->push_chunk_name[0] <41 || png_ptr->push_chunk_name[0]> 122 ||
+          (png_ptr->push_chunk_name[0]>90 && png_ptr->push_chunk_name[0]< 97) ||
+          png_ptr->push_chunk_name[1] <41 || png_ptr->push_chunk_name[1]> 122 ||
+          (png_ptr->push_chunk_name[1]>90 && png_ptr->push_chunk_name[1]< 97) ||
+          png_ptr->push_chunk_name[2] <41 || png_ptr->push_chunk_name[2]> 122 ||
+          (png_ptr->push_chunk_name[2]>90 && png_ptr->push_chunk_name[2]< 97) ||
+          png_ptr->push_chunk_name[3] <41 || png_ptr->push_chunk_name[3]> 122 ||
+          (png_ptr->push_chunk_name[3]>90 && png_ptr->push_chunk_name[3]< 97))
+      {
+         char msg[200];
+
+         sprintf(msg, "Invalid chunk type 0x%02X 0x%02X 0x%02X 0x%02X",
+            png_ptr->push_chunk_name[0], png_ptr->push_chunk_name[1],
+            png_ptr->push_chunk_name[2], png_ptr->push_chunk_name[3]);
+         png_error(png_ptr, msg);
+      }
+
       if ((png_ptr->push_chunk_name[0] & 0x20) == 0)
-         png_error(png_ptr, "Unknown Critical Chunk");
+      {
+         char msg[200];
+
+         sprintf(msg, "Unknown critical chunk %c%c%c%c",
+            png_ptr->push_chunk_name[0], png_ptr->push_chunk_name[1],
+            png_ptr->push_chunk_name[2], png_ptr->push_chunk_name[3]);
+         png_error(png_ptr, msg);
+      }
 
       png_push_crc_skip(png_ptr, png_ptr->push_length);
    }
-   png_ptr->have_chunk_header = 0;
+   png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
 }
 
 void
@@ -513,9 +537,9 @@ png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
 }
 
 void
-png_push_read_idat(png_structp png_ptr)
+png_push_read_IDAT(png_structp png_ptr)
 {
-   if (!png_ptr->have_chunk_header)
+   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_start[8];
 
@@ -529,13 +553,13 @@ png_push_read_idat(png_structp png_ptr)
       png_ptr->push_length = png_get_uint_32(chunk_start);
       png_memcpy(png_ptr->push_chunk_name,
          (png_voidp)(chunk_start + 4), 4);
-      png_ptr->have_chunk_header = 1;
+      png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
       png_reset_crc(png_ptr);
       png_calculate_crc(png_ptr, chunk_start + 4, 4);
       if (png_memcmp(png_ptr->push_chunk_name, png_IDAT, 4))
       {
          png_ptr->process_mode = PNG_READ_END_MODE;
-         if (!png_ptr->zlib_finished)
+         if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
             png_error(png_ptr, "Not enough compressed data");
          return;
       }
@@ -585,7 +609,7 @@ png_push_read_idat(png_structp png_ptr)
       }
 
       png_push_check_crc(png_ptr);
-      png_ptr->have_chunk_header = 0;
+      png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
    }
 }
 
@@ -595,7 +619,7 @@ png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
 {
    int ret;
 
-   if (png_ptr->zlib_finished && buffer_length)
+   if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
       png_error(png_ptr, "Extra compression data");
 
    png_ptr->zstream->next_in = buffer;
@@ -612,11 +636,11 @@ png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
             png_push_process_row(png_ptr);
          }
          png_ptr->mode = PNG_AT_LAST_IDAT;
-         png_ptr->zlib_finished = 1;
+         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
          break;
       }
       if (ret != Z_OK)
-         png_error(png_ptr, "Compression Error");
+         png_error(png_ptr, "Decompression Error");
       if (!(png_ptr->zstream->avail_out))
       {
          png_push_process_row(png_ptr);
@@ -638,8 +662,7 @@ png_push_process_row(png_structp png_ptr)
    png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
       (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
 
-   if (png_ptr->row_buf[0])
+   png_read_filter_row(png_ptr, &(png_ptr->row_info),
-      png_read_filter_row(&(png_ptr->row_info),
       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
       (int)(png_ptr->row_buf[0]));
 
@@ -811,7 +834,7 @@ void
 png_push_handle_PLTE(png_structp png_ptr, png_uint_32 length)
 {
    if (length % 3)
-      png_error(png_ptr, "Invalid Palette Chunk");
+      png_error(png_ptr, "Invalid palette chunk");
 
    png_ptr->num_palette = (png_uint_16)(length / 3);
    png_ptr->cur_palette = 0;
@@ -821,7 +844,7 @@ png_push_handle_PLTE(png_structp png_ptr, png_uint_32 length)
 }
 
 void
-png_push_read_plte(png_structp png_ptr, png_infop info)
+png_push_read_PLTE(png_structp png_ptr, png_infop info)
 {
    while (png_ptr->cur_palette < png_ptr->num_palette &&
       png_ptr->buffer_size >= 3)
@@ -862,7 +885,7 @@ png_push_handle_tEXt(png_structp png_ptr, png_uint_32 length)
 }
 
 void
-png_push_read_text(png_structp png_ptr, png_infop info)
+png_push_read_tEXt(png_structp png_ptr, png_infop info)
 {
    if (png_ptr->buffer_size && png_ptr->current_text_left)
    {
@@ -931,7 +954,7 @@ png_push_handle_zTXt(png_structp png_ptr,
 }
 
 void
-png_push_read_ztxt(png_structp png_ptr, png_infop info)
+png_push_read_zTXt(png_structp png_ptr, png_infop info)
 {
    if (png_ptr->buffer_size && png_ptr->current_text_left)
    {
@@ -1105,13 +1128,13 @@ png_push_have_row(png_structp png_ptr, png_bytep row)
 png_voidp
 png_get_progressive_ptr(png_structp png_ptr)
 {
-   return png_ptr->push_ptr;
+   return png_ptr->io_ptr;
 }
 
 void
 png_push_read_end(png_structp png_ptr, png_infop info)
 {
-   if (!png_ptr->have_chunk_header)
+   if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
    {
       png_byte chunk_start[8];
 
@@ -1124,23 +1147,23 @@ png_push_read_end(png_structp png_ptr, png_infop info)
       png_push_fill_buffer(png_ptr, chunk_start, 8);
       png_ptr->push_length = png_get_uint_32(chunk_start);
       png_memcpy(png_ptr->push_chunk_name, (png_voidp)(chunk_start + 4), 4);
-      png_ptr->have_chunk_header = 1;
+      png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
       png_reset_crc(png_ptr);
       png_calculate_crc(png_ptr, chunk_start + 4, 4);
    }
 
    if (!png_memcmp(png_ptr->push_chunk_name, png_IHDR, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid IHDR after IDAT");
    }
    else if (!png_memcmp(png_ptr->push_chunk_name, png_PLTE, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid PLTE after IDAT");
    }
    else if (!png_memcmp(png_ptr->push_chunk_name, png_IDAT, 4))
    {
       if (png_ptr->push_length > 0 || png_ptr->mode != PNG_AT_LAST_IDAT)
-         png_error(png_ptr, "too many IDAT's found");
+         png_error(png_ptr, "Too many IDAT's found");
    }
    else if (!png_memcmp(png_ptr->push_chunk_name, png_IEND, 4))
    {
@@ -1159,49 +1182,49 @@ png_push_read_end(png_structp png_ptr, png_infop info)
 #if defined(PNG_READ_gAMA_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_gAMA, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid gAMA after IDAT");
    }
 #endif
 #if defined(PNG_READ_sBIT_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_sBIT, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid sBIT after IDAT");
    }
 #endif
 #if defined(PNG_READ_cHRM_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_cHRM, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid cHRM after IDAT");
    }
 #endif
 #if defined(PNG_READ_tRNS_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_tRNS, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid tRNS after IDAT");
    }
 #endif
 #if defined(PNG_READ_bKGD_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_bKGD, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid bKGD after IDAT");
    }
 #endif
 #if defined(PNG_READ_hIST_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_hIST, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid hIST after IDAT");
    }
 #endif
 #if defined(PNG_READ_pHYs_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_pHYs, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid pHYs after IDAT");
    }
 #endif
 #if defined(PNG_READ_oFFs_SUPPORTED)
    else if (!png_memcmp(png_ptr->push_chunk_name, png_oFFs, 4))
    {
-      png_error(png_ptr, "invalid chunk after IDAT");
+      png_error(png_ptr, "Invalid oFFs after IDAT");
    }
 #endif
 #if defined(PNG_READ_tIME_SUPPORTED)
@@ -1215,7 +1238,7 @@ png_push_read_end(png_structp png_ptr, png_infop info)
 
       if (png_ptr->mode == PNG_BEFORE_IHDR ||
          png_ptr->mode == PNG_AFTER_IEND)
-         png_error(png_ptr, "Out of Place tIME");
+         png_error(png_ptr, "Out of place tIME");
 
       png_handle_tIME(png_ptr, info, png_ptr->push_length);
       png_push_check_crc(png_ptr);
@@ -1226,7 +1249,7 @@ png_push_read_end(png_structp png_ptr, png_infop info)
    {
       if (png_ptr->mode == PNG_BEFORE_IHDR ||
          png_ptr->mode == PNG_AFTER_IEND)
-         png_error(png_ptr, "Out of Place tEXt");
+         png_error(png_ptr, "Out of place tEXt");
 
       png_push_handle_tEXt(png_ptr, png_ptr->push_length);
    }
@@ -1236,21 +1259,45 @@ png_push_read_end(png_structp png_ptr, png_infop info)
    {
       if (png_ptr->mode == PNG_BEFORE_IHDR ||
          png_ptr->mode == PNG_AFTER_IEND)
-         png_error(png_ptr, "Out of Place zTXt");
+         png_error(png_ptr, "Out of place zTXt");
 
       png_push_handle_zTXt(png_ptr, png_ptr->push_length);
    }
 #endif
    else
    {
+      if (png_ptr->push_chunk_name[0] <41 || png_ptr->push_chunk_name[0]> 122 ||
+          (png_ptr->push_chunk_name[0]>90 && png_ptr->push_chunk_name[0]< 97) ||
+          png_ptr->push_chunk_name[1] <41 || png_ptr->push_chunk_name[1]> 122 ||
+          (png_ptr->push_chunk_name[1]>90 && png_ptr->push_chunk_name[1]< 97) ||
+          png_ptr->push_chunk_name[2] <41 || png_ptr->push_chunk_name[2]> 122 ||
+          (png_ptr->push_chunk_name[2]>90 && png_ptr->push_chunk_name[2]< 97) ||
+          png_ptr->push_chunk_name[3] <41 || png_ptr->push_chunk_name[3]> 122 ||
+          (png_ptr->push_chunk_name[3]>90 && png_ptr->push_chunk_name[3]< 97))
+      {
+         char msg[45];
+
+         sprintf(msg, "Invalid chunk type 0x%02X 0x%02X 0x%02X 0x%02X",
+            png_ptr->push_chunk_name[0], png_ptr->push_chunk_name[1],
+            png_ptr->push_chunk_name[2], png_ptr->push_chunk_name[3]);
+         png_error(png_ptr, msg);
+      }
+
       if ((png_ptr->push_chunk_name[0] & 0x20) == 0)
-         png_error(png_ptr, "Unknown Critical Chunk");
+      {
+         char msg[40];
+
+         sprintf(msg, "Unknown critical chunk %c%c%c%c",
+            png_ptr->push_chunk_name[0], png_ptr->push_chunk_name[1],
+            png_ptr->push_chunk_name[2], png_ptr->push_chunk_name[3]);
+         png_error(png_ptr, msg);
+      }
 
       png_push_crc_skip(png_ptr, png_ptr->push_length);
    }
    if (png_ptr->mode == PNG_AT_LAST_IDAT)
       png_ptr->mode = PNG_AFTER_IDAT;
-   png_ptr->have_chunk_header = 0;
+   png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
 }
 
 void
@@ -1260,9 +1307,9 @@ png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
 {
    png_ptr->info_fn = info_fn;
    png_ptr->row_fn = row_fn;
-   png_ptr->push_ptr = progressive_ptr;
    png_ptr->end_fn = end_fn;
-   png_ptr->read_mode = PNG_READ_PUSH_MODE;
+
+   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
 }
 
 void

pngrcb.c

@@ -1,9 +1,9 @@
 /* pngrcb.c - callbacks while reading a png file
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -185,7 +185,7 @@ png_read_tIME(png_structp png_ptr, png_infop info,
 }
 #endif
 
-#if defined(PNG_READ_zTXt_SUPPORTED)
+#if defined(PNG_READ_tEXt_SUPPORTED) || defined(PNG_READ_zTXt_SUPPORTED)
 void
 png_read_zTXt(png_structp png_ptr, png_infop info,
    png_charp key, png_charp text, png_uint_32 text_len, int compression)
@@ -214,10 +214,10 @@ png_read_zTXt(png_structp png_ptr, png_infop info,
       }
       else
       {
-         info->max_text = info->num_text + 16;
+         info->max_text = 16;
+         info->num_text = 0;
          info->text = (png_textp)png_large_malloc(png_ptr,
             info->max_text * sizeof (png_text));
-         info->num_text = 0;
       }
    }
 

pngread.c

@@ -1,45 +1,116 @@
 
 /* pngread.c - read a png file
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
 #include "png.h"
 
-/* initialize png structure for reading, and allocate any memory needed */
+/* Create a png structure for reading, and allocate any memory needed. */
-void
+png_structp
-png_read_init(png_structp png_ptr)
+png_create_read_struct(png_const_charp user_png_ver, voidp error_ptr,
+   png_error_ptr warn_fn, png_error_ptr error_fn)
 {
-   jmp_buf tmp_jmp;
+   png_structp png_ptr;
-   png_msg_ptr error_fn;
-   png_msg_ptr warning_fn;
-   png_voidp msg_ptr;
 
-   png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
+   if ((png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG)) == NULL)
-   error_fn = png_ptr->error_fn;
+   {
-   warning_fn = png_ptr->warning_fn;
+      return (png_structp)NULL;
-   msg_ptr = png_ptr->msg_ptr;
+   }
 
-   png_memset(png_ptr, 0, sizeof (png_struct));
+   if (setjmp(png_ptr->jmpbuf))
+   {
+      png_large_free(png_ptr, png_ptr->zbuf);
+      png_free(png_ptr, png_ptr->zstream);
+      png_destroy_struct(png_ptr);
+      return (png_structp)NULL;
+   }
 
-   png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
+   png_set_error_fn(png_ptr, error_ptr, warn_fn, error_fn);
-   png_ptr->error_fn = error_fn;
-   png_ptr->warning_fn = warning_fn;
-   png_ptr->msg_ptr = msg_ptr;
 
+   if (user_png_ver == NULL || strcmp(user_png_ver, png_libpng_ver))
+   {
+      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0])
+      {
+         png_error(png_ptr, "Incompatible libpng versions");
+      }
+      else
+      {
+         png_warning(png_ptr, "Different libpng versions");
+      }
+   }
+
+   /* initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = png_large_malloc(png_ptr, png_ptr->zbuf_size);
+
    png_ptr->zstream = (z_stream *)png_malloc(png_ptr, sizeof (z_stream));
    png_ptr->zstream->zalloc = png_zalloc;
    png_ptr->zstream->zfree = png_zfree;
    png_ptr->zstream->opaque = (voidpf)png_ptr;
-   inflateInit(png_ptr->zstream);
+
+   switch (inflateInit(png_ptr->zstream))
+   {
+     case Z_OK: /* Do nothing */ break;
+     case Z_MEM_ERROR:
+     case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
+     case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
+     default: png_error(png_ptr, "Unknown zlib error");
+   }
+
    png_ptr->zstream->next_out = png_ptr->zbuf;
    png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
+
+   png_set_read_fn(png_ptr, NULL, NULL);
+
+   png_ptr->do_free |= PNG_FREE_STRUCT;
+
+   return (png_ptr);
+}
+
+
+/* initialize png structure for reading, and allocate any memory needed */
+/* This interface is depreciated in favour of the png_create_read_struct() */
+void
+png_read_init(png_structp png_ptr)
+{
+   jmp_buf tmp_jmp;  /* to save current jump buffer */
+
+   /* save jump buffer and error functions */
+   png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
+
+   /* reset all variables to 0 */
+   png_memset(png_ptr, 0, sizeof (png_struct));
+
+   /* restore jump buffer */
+   png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
+
+   /* initialize zbuf - compression buffer */
+   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
+   png_ptr->zbuf = png_large_malloc(png_ptr, png_ptr->zbuf_size);
+
+   png_ptr->zstream = (z_stream *)png_malloc(png_ptr, sizeof (z_stream));
+   png_ptr->zstream->zalloc = png_zalloc;
+   png_ptr->zstream->zfree = png_zfree;
+   png_ptr->zstream->opaque = (voidpf)png_ptr;
+
+   switch (inflateInit(png_ptr->zstream))
+   {
+     case Z_OK: /* Do nothing */ break;
+     case Z_MEM_ERROR:
+     case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
+     case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
+     default: png_error(png_ptr, "Unknown zlib error");
+   }
+
+   png_ptr->zstream->next_out = png_ptr->zbuf;
+   png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
+
+   png_set_read_fn(png_ptr, NULL, NULL);
 }
 
 /* read the information before the actual image data. */
@@ -50,8 +121,13 @@ png_read_info(png_structp png_ptr, png_infop info)
    png_uint_32 length;
 
    png_read_data(png_ptr, chunk_start, 8);
-   if (png_memcmp(chunk_start, png_sig, 8))
+   if (!png_check_sig(chunk_start, 8))
-      png_error(png_ptr, "Not a Png File");
+   {
+      if (!png_check_sig(chunk_start, 4))
+         png_error(png_ptr, "Not a PNG file");
+      else
+         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+   }
 
    while (1)
    {
@@ -62,167 +138,110 @@ png_read_info(png_structp png_ptr, png_infop info)
       png_reset_crc(png_ptr);
       png_calculate_crc(png_ptr, chunk_start + 4, 4);
       if (!png_memcmp(chunk_start + 4, png_IHDR, 4))
-      {
-         if (png_ptr->mode != PNG_BEFORE_IHDR)
-            png_error(png_ptr, "Out of Place IHDR");
-
          png_handle_IHDR(png_ptr, info, length);
-         png_ptr->mode = PNG_HAVE_IHDR;
-      }
       else if (!png_memcmp(chunk_start + 4, png_PLTE, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR)
-            png_error(png_ptr, "Missing IHDR");
-
-#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
-         if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
-            png_crc_skip(png_ptr, length);
-         else
-#else
-         {
          png_handle_PLTE(png_ptr, info, length);
-         }
-#endif
-         png_ptr->mode = PNG_HAVE_PLTE;
-      }
       else if (!png_memcmp(chunk_start + 4, png_IDAT, 4))
       {
+         if (!(png_ptr->mode & PNG_HAVE_IHDR))
+            png_error(png_ptr, "Missing IHDR before IDAT");
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+                  !(png_ptr->mode & PNG_HAVE_PLTE))
+            png_error(png_ptr, "Missing PLTE before IDAT");
+
          png_ptr->idat_size = length;
-         png_ptr->mode = PNG_HAVE_IDAT;
+         png_ptr->mode |= PNG_HAVE_IDAT;
          break;
       }
       else if (!png_memcmp(chunk_start + 4, png_IEND, 4))
-      {
+         png_error(png_ptr, "No image in file");
-         png_error(png_ptr, "No Image in File");
-      }
 #if defined(PNG_READ_gAMA_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_gAMA, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR)
-            png_error(png_ptr, "Out of Place PLTE");
-
          png_handle_gAMA(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_sBIT_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_sBIT, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR)
-            png_error(png_ptr, "Out of Place sBIT");
-
          png_handle_sBIT(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_cHRM_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_cHRM, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR)
-            png_error(png_ptr, "Out of Place cHRM");
-
          png_handle_cHRM(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_tRNS_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_tRNS, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR &&
-            png_ptr->mode != PNG_HAVE_PLTE)
-            png_error(png_ptr, "Out of Place tRNS");
-
          png_handle_tRNS(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_bKGD_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_bKGD, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR &&
-            png_ptr->mode != PNG_HAVE_PLTE)
-            png_error(png_ptr, "Out of Place bKGD");
-
          png_handle_bKGD(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_hIST_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_hIST, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_PLTE)
-            png_error(png_ptr, "Out of Place hIST");
-
          png_handle_hIST(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_pHYs_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_pHYs, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR &&
-            png_ptr->mode != PNG_HAVE_PLTE)
-            png_error(png_ptr, "Out of Place pHYs");
-
          png_handle_pHYs(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_oFFs_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_oFFs, 4))
-      {
-         if (png_ptr->mode != PNG_HAVE_IHDR &&
-            png_ptr->mode != PNG_HAVE_PLTE)
-            png_error(png_ptr, "Out of Place oFFs");
-
          png_handle_oFFs(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_tIME_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_tIME, 4))
-      {
-         if (png_ptr->mode == PNG_BEFORE_IHDR ||
-            png_ptr->mode == PNG_AFTER_IEND)
-            png_error(png_ptr, "Out of Place tIME");
-
          png_handle_tIME(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_tEXt_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_tEXt, 4))
-      {
-         if (png_ptr->mode == PNG_BEFORE_IHDR ||
-            png_ptr->mode == PNG_AFTER_IEND)
-            png_error(png_ptr, "Out of Place tEXt");
-
          png_handle_tEXt(png_ptr, info, length);
-      }
 #endif
 #if defined(PNG_READ_zTXt_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_zTXt, 4))
-      {
-         if (png_ptr->mode == PNG_BEFORE_IHDR ||
-            png_ptr->mode == PNG_AFTER_IEND)
-            png_error(png_ptr, "Out of Place zTXt");
-
          png_handle_zTXt(png_ptr, info, length);
-      }
 #endif
       else
       {
+         if (chunk_start[4] < 41 || chunk_start[4] > 122  ||
+             (chunk_start[4] > 90 && chunk_start[4] < 97) ||
+             chunk_start[5] < 41 || chunk_start[5] > 122  ||
+             (chunk_start[5] > 90 && chunk_start[5] < 97) ||
+             chunk_start[6] < 41 || chunk_start[6] > 122  ||
+             (chunk_start[6] > 90 && chunk_start[6] < 97) ||
+             chunk_start[7] < 41 || chunk_start[7] > 122  ||
+             (chunk_start[7] > 90 && chunk_start[7] < 97))
+         {
+            char msg[45];
+
+            sprintf(msg, "Invalid chunk type 0x%02X 0x%02X 0x%02X 0x%02X",
+               chunk_start[4], chunk_start[5], chunk_start[6], chunk_start[7]);
+            png_error(png_ptr, msg);
+         }
+
          if ((chunk_start[4] & 0x20) == 0)
-            png_error(png_ptr, "Unknown Critical Chunk");
+         {
+            char msg[40];
+
+            sprintf(msg, "Unknown critical chunk %c%c%c%c",
+               chunk_start[4], chunk_start[5], chunk_start[6], chunk_start[7]);
+            png_error(png_ptr, msg);
+         }
 
          png_crc_skip(png_ptr, length);
       }
       png_read_data(png_ptr, chunk_start, 4);
       crc = png_get_uint_32(chunk_start);
-      if (((crc ^ 0xffffffffL) & 0xffffffffL) !=
+      if (((crc ^ 0xffffffffL) & 0xffffffffL) != (png_ptr->crc & 0xffffffffL))
-         (png_ptr->crc & 0xffffffffL))
          png_error(png_ptr, "Bad CRC value");
    }
 }
 
 /* optional call to update the users info structure */
 void
-png_read_update_info(png_structp png_ptr, png_infop info_ptr)
+png_read_update_info(png_structp png_ptr, png_infop info)
 {
-   if (!(png_ptr->row_init))
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
-   png_read_transform_info(png_ptr, info_ptr);
+   png_read_transform_info(png_ptr, info);
 }
 
 /* initialize palette, background, etc, after transformations
@@ -232,7 +251,7 @@ png_read_update_info(png_structp png_ptr, png_infop info_ptr)
 void
 png_start_read_image(png_structp png_ptr)
 {
-   if (!(png_ptr->row_init))
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
 }
 
@@ -240,7 +259,7 @@ void
 png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 {
    int ret;
-   if (!(png_ptr->row_init))
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
       png_read_start_row(png_ptr);
 
 #if defined(PNG_READ_INTERLACING_SUPPORTED)
@@ -320,8 +339,8 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
    }
 #endif
 
-   if (png_ptr->mode != PNG_HAVE_IDAT)
+   if (!(png_ptr->mode & PNG_HAVE_IDAT))
-      png_error(png_ptr, "invalid attempt to read row data");
+      png_error(png_ptr, "Invalid attempt to read row data");
 
    png_ptr->zstream->next_out = png_ptr->row_buf;
    png_ptr->zstream->avail_out = (uInt)png_ptr->irowbytes;
@@ -346,8 +365,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
 
             png_crc_read(png_ptr, buf, 4);
             if (png_memcmp(buf, png_IDAT, 4))
-               png_error(png_ptr, "Not enough image data");
+               png_error(png_ptr, "Not enough IDATs for image");
-
          }
          png_ptr->zstream->avail_in = (uInt)png_ptr->zbuf_size;
          png_ptr->zstream->next_in = png_ptr->zbuf;
@@ -362,17 +380,15 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
          if (png_ptr->zstream->avail_out || png_ptr->zstream->avail_in ||
             png_ptr->idat_size)
             png_error(png_ptr, "Extra compressed data");
-         png_ptr->mode = PNG_AT_LAST_IDAT;
+         png_ptr->mode |= PNG_AT_LAST_IDAT;
+         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
          break;
       }
       if (ret != Z_OK)
-         png_error(png_ptr, "Compression Error");
+         png_error(png_ptr, png_ptr->zstream->msg ? png_ptr->zstream->msg :
-
+                   "Decompression error");
    } while (png_ptr->zstream->avail_out);
 
-   if (ret == Z_STREAM_END)
-      png_ptr->zlib_finished = 1;
-
    png_ptr->row_info.color_type = png_ptr->color_type;
    png_ptr->row_info.width = png_ptr->iwidth;
    png_ptr->row_info.channels = png_ptr->channels;
@@ -381,8 +397,7 @@ png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
    png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
       (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
 
-   if (png_ptr->row_buf[0])
+   png_read_filter_row(png_ptr, &(png_ptr->row_info),
-      png_read_filter_row(&(png_ptr->row_info),
       png_ptr->row_buf + 1, png_ptr->prev_row + 1,
       (int)(png_ptr->row_buf[0]));
 
@@ -471,9 +486,12 @@ png_read_rows(png_structp png_ptr, png_bytepp row,
 /* read the image.  If the image has an alpha channel or a transparency
    chunk, and you have called png_handle_alpha(), you will need to
    initialize the image to the current image that png will be overlaying.
-   Note that png_set_interlace_handling() has no effect on this call.
+   We set the num_rows again here, in case it was incorrectly set in
-   You only need to call this function once.  If you desire to have
+   png_read_start_row() by a call to png_read_update_info() or
-   an image for each pass of a interlaced image, use png_read_rows() */
+   png_start_read_image() if png_set_interlace_handling() wasn't called
+   prior to either of these functions like it should have been.  You only
+   need to call this function once.  If you desire to have an image for
+   each pass of a interlaced image, use png_read_rows() instead */
 void
 png_read_image(png_structp png_ptr, png_bytepp image)
 {
@@ -482,6 +500,9 @@ png_read_image(png_structp png_ptr, png_bytepp image)
    png_bytepp rp;
 
    pass = png_set_interlace_handling(png_ptr);
+
+   png_ptr->num_rows = png_ptr->height; /* Make sure this is set correctly */
+
    for (j = 0; j < pass; j++)
    {
       rp = image;
@@ -518,55 +539,53 @@ png_read_end(png_structp png_ptr, png_infop info)
 
       if (!png_memcmp(chunk_start + 4, png_IHDR, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid IHDR after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_PLTE, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid PLTE after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_gAMA, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid gAMA after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_sBIT, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid sBIT after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_cHRM, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid cHRM after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_tRNS, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid tRNS after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_bKGD, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid bKGD after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_hIST, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid hIST after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_IDAT, 4))
       {
-         if (length > 0 || png_ptr->mode != PNG_AT_LAST_IDAT)
+         if (length > 0 || png_ptr->mode & PNG_AFTER_IDAT)
-            png_error(png_ptr, "too many IDAT's found");
+            png_error(png_ptr, "Too many IDAT's found");
       }
       else if (!png_memcmp(chunk_start + 4, png_pHYs, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid pHYs after IDAT");
       }
       else if (!png_memcmp(chunk_start + 4, png_oFFs, 4))
       {
-         png_error(png_ptr, "invalid chunk after IDAT");
+         png_error(png_ptr, "Invalid oFFs after IDAT");
       }
 #if defined(PNG_READ_tIME_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_tIME, 4))
       {
-         if (png_ptr->mode == PNG_BEFORE_IHDR ||
+         png_ptr->mode |= PNG_AFTER_IDAT;
-            png_ptr->mode == PNG_AFTER_IEND)
-            png_error(png_ptr, "Out of Place tIME");
 
          if (info)
             png_handle_tIME(png_ptr, info, length);
@@ -577,9 +596,7 @@ png_read_end(png_structp png_ptr, png_infop info)
 #if defined(PNG_READ_tEXt_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_tEXt, 4))
       {
-         if (png_ptr->mode == PNG_BEFORE_IHDR ||
+         png_ptr->mode |= PNG_AFTER_IDAT;
-            png_ptr->mode == PNG_AFTER_IEND)
-            png_error(png_ptr, "Out of Place tEXt");
 
          if (info)
             png_handle_tEXt(png_ptr, info, length);
@@ -590,9 +607,7 @@ png_read_end(png_structp png_ptr, png_infop info)
 #if defined(PNG_READ_zTXt_SUPPORTED)
       else if (!png_memcmp(chunk_start + 4, png_zTXt, 4))
       {
-         if (png_ptr->mode == PNG_BEFORE_IHDR ||
+         png_ptr->mode |= PNG_AFTER_IDAT;
-            png_ptr->mode == PNG_AFTER_IEND)
-            png_error(png_ptr, "Out of Place zTXt");
 
          if (info)
             png_handle_zTXt(png_ptr, info, length);
@@ -602,31 +617,83 @@ png_read_end(png_structp png_ptr, png_infop info)
 #endif
       else if (!png_memcmp(chunk_start + 4, png_IEND, 4))
       {
-         png_ptr->mode = PNG_AFTER_IEND;
+         png_ptr->mode |= PNG_AFTER_IDAT;
+         png_ptr->mode |= PNG_AFTER_IEND;
       }
       else
       {
-         if ((chunk_start[4] & 0x20) == 0)
+         if (chunk_start[4] < 41 || chunk_start[4] > 122  ||
-            png_error(png_ptr, "Unknown Critical Chunk");
+             (chunk_start[4] > 90 && chunk_start[4] < 97) ||
+             chunk_start[5] < 41 || chunk_start[5] > 122  ||
+             (chunk_start[5] > 90 && chunk_start[5] < 97) ||
+             chunk_start[6] < 41 || chunk_start[6] > 122  ||
+             (chunk_start[6] > 90 && chunk_start[6] < 97) ||
+             chunk_start[7] < 41 || chunk_start[7] > 122  ||
+             (chunk_start[7] > 90 && chunk_start[7] < 97))
+         {
+           png_error(png_ptr, "Invalid chunk type");
+         }
 
+         if ((chunk_start[4] & 0x20) == 0)
+            png_error(png_ptr, "Unknown critical chunk");
+
+         png_ptr->mode |= PNG_AFTER_IDAT;
          png_crc_skip(png_ptr, length);
       }
       png_read_data(png_ptr, chunk_start, 4);
       crc = png_get_uint_32(chunk_start);
-      if (((crc ^ 0xffffffffL) & 0xffffffffL) !=
+      if (((crc ^ 0xffffffffL) & 0xffffffffL) != (png_ptr->crc & 0xffffffffL))
-         (png_ptr->crc & 0xffffffffL))
          png_error(png_ptr, "Bad CRC value");
-      if (png_ptr->mode == PNG_AT_LAST_IDAT)
+   } while (!(png_ptr->mode & PNG_AFTER_IEND));
-         png_ptr->mode = PNG_AFTER_IDAT;
-   } while (png_ptr->mode != PNG_AFTER_IEND);
 }
 
 /* free all memory used by the read */
 void
+png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
+   png_infopp end_info_ptr)
+{
+   png_structp png_ptr = NULL;
+   png_infop info_ptr = NULL, end_info = NULL;
+
+   if (png_ptr_ptr)
+      png_ptr = *png_ptr_ptr;
+
+   if (info_ptr_ptr)
+      info_ptr = *info_ptr_ptr;
+
+   if (end_info_ptr)
+      end_info = *end_info_ptr;
+
+   png_read_destroy(png_ptr, info_ptr, end_info);
+
+   if (info_ptr)
+   {
+      png_destroy_struct((voidp)info_ptr);
+      *info_ptr_ptr = (png_infop)NULL;
+   }
+
+   if (end_info)
+   {
+      png_destroy_struct((voidp)end_info);
+      *end_info_ptr = (png_infop)NULL;
+   }
+
+   if (png_ptr)
+   {
+      png_destroy_struct((voidp)png_ptr);
+      *png_ptr_ptr = (png_structp)NULL;
+   }
+}
+
+/* free all memory used by the read (old) */
+void
 png_read_destroy(png_structp png_ptr, png_infop info, png_infop end_info)
 {
    int i;
    jmp_buf tmp_jmp;
+   png_error_ptr error_fn;
+   png_error_ptr warning_fn;
+   png_voidp error_ptr;
 
    if (info)
    {
@@ -712,8 +779,21 @@ png_read_destroy(png_structp png_ptr, png_infop info, png_infop end_info)
 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
    png_large_free(png_ptr, png_ptr->save_buffer);
 #endif
+
+   /* Save the important info out of the png_struct, in case it is
+    * being used again.
+    */
    png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
+
+   error_fn = png_ptr->error_fn;
+   warning_fn = png_ptr->warning_fn;
+   error_ptr = png_ptr->error_ptr;
+
    png_memset(png_ptr, 0, sizeof (png_struct));
+
+   png_ptr->error_fn = error_fn;
+   png_ptr->warning_fn = warning_fn;
+   png_ptr->error_ptr = error_ptr;
+
    png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
 }
-

pngrio.c

@@ -0,0 +1,141 @@
+
+/* pngrio.c - functions for data input
+
+   libpng 1.0 beta 3 - version 0.89
+   For conditions of distribution and use, see copyright notice in png.h
+   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+   May 25, 1996
+
+   This file provides a location for all input.  Users which need
+   special handling are expected to write a function which has the same
+   arguments as this, and perform a similar function, but possibly has
+   a different input method.  Note that you shouldn't change this
+   function, but rather write a replacement function and then make
+   libpng use it at run time with png_set_read_fn(...) */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+/* Read the data from whatever input you are using.  The default routine
+   reads from a file pointer.  Note that this routine sometimes gets called
+   with very small lengths, so you should implement some kind of simple
+   buffering if you are using unbuffered reads.  This should never be asked
+   to read more then 64K on a 16 bit machine.  The cast to png_size_t is
+   there to quiet some compilers */
+void
+png_read_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
+{
+   if (png_ptr->read_data_fn)
+      (*(png_ptr->read_data_fn))(png_ptr, data, length);
+   else
+      png_error(png_ptr, "Call to NULL read function");
+}
+
+/* This is the function which does the actual reading of data.  If you are
+   not reading from a standard C stream, you should create a replacement
+   read_data function and use it at run time with png_set_read_fn(), rather
+   than changing the library. */
+#ifndef USE_FAR_KEYWORD
+static void
+png_default_read_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
+{
+   png_uint_32 check;
+
+   check = fread(data, 1, (size_t)length, (FILE *)png_ptr->io_ptr);
+   if (check != length)
+   {
+      png_error(png_ptr, "Read Error");
+   }
+}
+#else
+/* this is the model-independent version. Since the standard I/O library
+   can't handle far buffers in the medium and small models, we have to copy
+   the data.
+*/
+ 
+#define NEAR_BUF_SIZE 1024
+#define MIN(a,b) (a <= b ? a : b)
+ 
+#ifdef _MSC_VER
+/* for FP_OFF */
+#include <dos.h>
+#endif
+ 
+static void
+png_default_read_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
+{
+   png_uint_32 check;
+   png_byte *n_data;
+
+   /* Check if data really is near. If so, use usual code. */
+#ifdef _MSC_VER
+   /* do it this way just to quiet warning */
+   FP_OFF(n_data) = FP_OFF(data);
+   if (FP_SEG(n_data) == FP_SEG(data))
+#else
+   /* this works in MSC also but with lost segment warning */
+   n_data = (png_byte *)data;
+   if ((png_bytep)n_data == data)
+#endif
+   {
+      check = fread(n_data, 1, (size_t)length, (FILE *)png_ptr->io_ptr);
+   }
+   else
+   {
+      png_byte buf[NEAR_BUF_SIZE];
+      png_size_t read, remaining, err;
+      check = 0;
+      remaining = (png_size_t)length;
+      do
+      {
+         read = MIN(NEAR_BUF_SIZE, remaining);
+         err = fread(buf, 1, read, (FILE *)png_ptr->io_ptr);
+         png_memcpy(data, buf, read); /* copy far buffer to near buffer */
+         if(err != read)
+            break;
+         else
+            check += err;
+         data += read;
+         remaining -= read;
+      }
+      while (remaining != 0);
+   }
+   if (check != length)
+   {
+      png_error(png_ptr, "read Error");
+   }
+}
+#endif
+
+/* This function allows the application to supply a new input function
+   for libpng if standard C streams aren't being used.
+
+   This function takes as its arguments:
+   png_ptr      - pointer to a png input data structure
+   io_ptr       - pointer to user supplied structure containing info about
+                  the input functions.  May be NULL.
+   read_data_fn - pointer to a new input function which takes as it's
+                  arguments a pointer to a png_struct, a pointer to
+                  a location where input data can be stored, and a 32-bit
+                  unsigned int which is the number of bytes to be read.
+                  To exit and output any fatal error messages the new write
+                  function should call png_error(png_ptr, "Error msg"). */
+void
+png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
+   png_rw_ptr read_data_fn)
+{
+   png_ptr->io_ptr = io_ptr;
+
+   if (read_data_fn)
+      png_ptr->read_data_fn = read_data_fn;
+   else
+      png_ptr->read_data_fn = png_default_read_data;
+
+   /* It is an error to write to a read device */
+   png_ptr->write_data_fn = NULL;
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+   png_ptr->output_flush_fn = NULL;
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+}
+

pngrtran.c

@@ -1,10 +1,10 @@
 
 /* pngrtran.c - transforms the data in a row for png readers
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -22,7 +22,7 @@ png_set_background(png_structp png_ptr,
       sizeof(png_color_16));
    png_ptr->background_gamma = (float)background_gamma;
    png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
-   png_ptr->background_expand = (png_byte)need_expand;
+   png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
 }
 #endif
 
@@ -353,7 +353,6 @@ png_set_dither(png_structp png_ptr, png_colorp palette,
    if (!(png_ptr->palette))
    {
       png_ptr->palette = palette;
-      png_ptr->user_palette = 1;
    }
    png_ptr->num_palette = (png_uint_16)num_palette;
 
@@ -468,45 +467,44 @@ png_init_read_transformations(png_structp png_ptr)
 
    color_type = png_ptr->color_type;
 
-#if defined(PNG_READ_EXPAND_SUPPORTED) && \
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
-    defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if (png_ptr->transformations & PNG_BACKGROUND_EXPAND)
-   if (png_ptr->transformations & PNG_EXPAND)
    {
-      if (color_type == PNG_COLOR_TYPE_GRAY &&
+      if (color_type == PNG_COLOR_TYPE_GRAY)
-         png_ptr->bit_depth < 8 &&
-         (png_ptr->transformations & PNG_BACKGROUND) &&
-         png_ptr->background_expand)
-/*         (!(png_ptr->transformations & PNG_BACKGROUND) ||
-         png_ptr->background_expand)) */
       {
-         /* expand background chunk.  While this may not be
+         /* expand background chunk. */
-            the fastest way to do this, it only happens once
-            per file. */
          switch (png_ptr->bit_depth)
          {
             case 1:
-               png_ptr->background.gray *= (png_byte)0xff;
+               png_ptr->background.gray *= (png_uint_16)0xff;
+               png_ptr->background.red = png_ptr->background.green =
+               png_ptr->background.blue = png_ptr->background.gray;
                break;
             case 2:
-               png_ptr->background.gray *= (png_byte)0x55;
+               png_ptr->background.gray *= (png_uint_16)0x55;
+               png_ptr->background.red = png_ptr->background.green =
+               png_ptr->background.blue = png_ptr->background.gray;
                break;
             case 4:
-               png_ptr->background.gray *= (png_byte)0x11;
+               png_ptr->background.gray *= (png_uint_16)0x11;
+               png_ptr->background.red = png_ptr->background.green =
+               png_ptr->background.blue = png_ptr->background.gray;
+               break;
+            case 8:
+            case 16:
+               png_ptr->background.red = png_ptr->background.green =
+               png_ptr->background.blue = png_ptr->background.gray;
                break;
          }
       }
-      if (color_type == PNG_COLOR_TYPE_PALETTE &&
+      else if (color_type == PNG_COLOR_TYPE_PALETTE)
-         (png_ptr->transformations & PNG_BACKGROUND) &&
-         png_ptr->background_expand)
       {
-         /* expand background chunk */
          png_ptr->background.red   =
             png_ptr->palette[png_ptr->background.index].red;
          png_ptr->background.green =
             png_ptr->palette[png_ptr->background.index].green;
          png_ptr->background.blue  =
             png_ptr->palette[png_ptr->background.index].blue;
-         color_type = PNG_COLOR_TYPE_RGB;
       }
    }
 #endif
@@ -519,10 +517,71 @@ png_init_read_transformations(png_structp png_ptr)
    {
       png_build_gamma_table(png_ptr);
 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
-      if ((png_ptr->transformations & PNG_BACKGROUND) &&
+      if (png_ptr->transformations & PNG_BACKGROUND)
-         (color_type != PNG_COLOR_TYPE_PALETTE))
       {
-         if (png_ptr->background_gamma_type != PNG_BACKGROUND_GAMMA_UNKNOWN)
+         if (color_type == PNG_COLOR_TYPE_PALETTE)
+         {
+            int num_palette, i;
+            png_color back, back_1;
+            png_colorp palette;
+
+            palette = png_ptr->palette;
+            num_palette = png_ptr->num_palette;
+
+            back.red = png_ptr->gamma_table[png_ptr->background.red];
+            back.green = png_ptr->gamma_table[png_ptr->background.green];
+            back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+
+            back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+            back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+            back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+
+            for (i = 0; i < num_palette; i++)
+            {
+               if (i < (int)png_ptr->num_trans)
+               {
+                  if (png_ptr->trans[i] == 0)
+                  {
+                     palette[i] = back;
+                  }
+                  else if (png_ptr->trans[i] != 0xff)
+                  {
+                     int v, w;
+
+                     v = png_ptr->gamma_to_1[palette[i].red];
+                     w = (int)(((png_uint_32)(v) *
+                        (png_uint_32)(png_ptr->trans[i]) +
+                        (png_uint_32)(back_1.red) *
+                        (png_uint_32)(255 - png_ptr->trans[i]) +
+                        127) / 255);
+                     palette[i].red = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].green];
+                     w = (int)(((png_uint_32)(v) *
+                        (png_uint_32)(png_ptr->trans[i]) +
+                        (png_uint_32)(back_1.green) *
+                        (png_uint_32)(255 - png_ptr->trans[i]) +
+                        127) / 255);
+                     palette[i].green = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].blue];
+                     w = (int)(((png_uint_32)(v) *
+                        (png_uint_32)(png_ptr->trans[i]) +
+                        (png_uint_32)(back_1.blue) *
+                        (png_uint_32)(255 - png_ptr->trans[i]) +
+                        127) / 255);
+                     palette[i].blue = png_ptr->gamma_from_1[w];
+                  }
+               }
+               else
+               {
+                  palette[i].red = png_ptr->gamma_table[palette[i].red];
+                  palette[i].green = png_ptr->gamma_table[palette[i].green];
+                  palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+               }
+            }
+         }
+         else if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN)
          {
             double g, gs, m;
 
@@ -571,7 +630,69 @@ png_init_read_transformations(png_structp png_ptr)
             }
          }
       }
+      else
 #endif
+      if (color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         int num_palette, i;
+         png_colorp palette;
+
+         palette = png_ptr->palette;
+         num_palette = png_ptr->num_palette;
+
+         for (i = 0; i < num_palette; i++)
+         {
+            palette[i].red = png_ptr->gamma_table[palette[i].red];
+            palette[i].green = png_ptr->gamma_table[palette[i].green];
+            palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+         }
+      }
+   }
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   else
+#endif
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if (png_ptr->transformations & PNG_BACKGROUND &&
+       color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      int i;
+      png_color back;
+      png_colorp palette;
+
+      palette = png_ptr->palette;
+      back.red   = (png_byte)png_ptr->background.red;
+      back.green = (png_byte)png_ptr->background.green;
+      back.blue  = (png_byte)png_ptr->background.blue;
+
+      for (i = 0; i < png_ptr->num_trans; i++)
+      {
+         if (png_ptr->trans[i] == 0)
+         {
+            palette[i] = back;
+         }
+         else if (png_ptr->trans[i] != 0xff)
+         {
+            palette[i].red = (png_byte)((
+               (png_uint_32)(palette[i].red) *
+               (png_uint_32)(png_ptr->trans[i]) +
+               (png_uint_32)(back.red) *
+               (png_uint_32)(255 - png_ptr->trans[i]) +
+               127) / 255);
+            palette[i].green = (png_byte)((
+               (png_uint_32)(palette[i].green) *
+               (png_uint_32)(png_ptr->trans[i]) +
+               (png_uint_32)(back.green) *
+               (png_uint_32)(255 - png_ptr->trans[i]) +
+               127) / 255);
+            palette[i].blue = (png_byte)((
+               (png_uint_32)(palette[i].blue) *
+               (png_uint_32)(png_ptr->trans[i]) +
+               (png_uint_32)(back.blue) *
+               (png_uint_32)(255 - png_ptr->trans[i]) +
+               127) / 255);
+         }
+      }
    }
 #endif
 
@@ -769,7 +890,7 @@ png_do_read_transformations(png_structp png_ptr)
 #if defined(PNG_READ_FILLER_SUPPORTED)
    if (png_ptr->transformations & PNG_FILLER)
       png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
-         png_ptr->filler, png_ptr->filler_loc);
+         png_ptr->filler, png_ptr->flags);
 #endif
 }
 
@@ -1002,14 +1123,14 @@ png_do_chop(png_row_infop row_info, png_bytep row)
 /* add filler byte */
 void
 png_do_read_filler(png_row_infop row_info, png_bytep row,
-   png_byte filler, png_byte filler_loc)
+   png_byte filler, png_byte flags)
 {
    png_bytep sp, dp;
    png_uint_32 i;
    if (row && row_info && row_info->color_type == 2 &&
       row_info->bit_depth == 8)
    {
-      if (filler_loc == PNG_FILLER_AFTER)
+      if (flags & PNG_FLAG_FILLER_AFTER)
       {
          for (i = 1, sp = row + (png_size_t)row_info->width * 3,
             dp = row + (png_size_t)row_info->width * 4;
@@ -1183,32 +1304,28 @@ png_build_grayscale_palette(int bit_depth, png_colorp palette)
    }
 }
 
-#if defined(PNG_READ_DITHER_SUPPORTED)
+/* This function is currently unused? */
+#if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_CORRECT_PALETTE_SUPPORTED)
 void
 png_correct_palette(png_structp png_ptr, png_colorp palette,
    int num_palette)
 {
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
    if ((png_ptr->transformations & (PNG_GAMMA)) &&
       (png_ptr->transformations & (PNG_BACKGROUND)))
    {
-      if (png_ptr->color_type == 3)
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
          int i;
          png_color back, back_1;
 
-         back.red = png_ptr->gamma_table[png_ptr->palette[
+         back.red = png_ptr->gamma_table[png_ptr->background.red];
-            png_ptr->background.index].red];
+         back.green = png_ptr->gamma_table[png_ptr->background.green];
-         back.green = png_ptr->gamma_table[png_ptr->palette[
+         back.blue = png_ptr->gamma_table[png_ptr->background.blue];
-            png_ptr->background.index].green];
-         back.blue = png_ptr->gamma_table[png_ptr->palette[
-            png_ptr->background.index].blue];
 
-         back_1.red = png_ptr->gamma_to_1[png_ptr->palette[
+         back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
-            png_ptr->background.index].red];
+         back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
-         back_1.green = png_ptr->gamma_to_1[png_ptr->palette[
+         back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
-            png_ptr->background.index].green];
-         back_1.blue = png_ptr->gamma_to_1[png_ptr->palette[
-            png_ptr->background.index].blue];
 
          for (i = 0; i < num_palette; i++)
          {
@@ -1256,17 +1373,18 @@ png_correct_palette(png_structp png_ptr, png_colorp palette,
       }
       else
       {
-         int i, back;
+         int i;
+         png_color back;
 
-         back = png_ptr->gamma_table[png_ptr->background.gray];
+         back.red = png_ptr->gamma_table[png_ptr->background.red];
+         back.green = png_ptr->gamma_table[png_ptr->background.green];
+         back.blue = png_ptr->gamma_table[png_ptr->background.blue];
 
          for (i = 0; i < num_palette; i++)
          {
             if (palette[i].red == png_ptr->trans_values.gray)
             {
-               palette[i].red = (png_byte)back;
+               palette[i] = back;
-               palette[i].green = (png_byte)back;
-               palette[i].blue = (png_byte)back;
             }
             else
             {
@@ -1277,7 +1395,10 @@ png_correct_palette(png_structp png_ptr, png_colorp palette,
          }
       }
    }
-   else if (png_ptr->transformations & (PNG_GAMMA))
+   else
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   if (png_ptr->transformations & (PNG_GAMMA))
    {
       int i;
 
@@ -1288,25 +1409,30 @@ png_correct_palette(png_structp png_ptr, png_colorp palette,
          palette[i].blue = png_ptr->gamma_table[palette[i].blue];
       }
    }
-   else if (png_ptr->transformations & (PNG_BACKGROUND))
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   else
+#endif
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if (png_ptr->transformations & (PNG_BACKGROUND))
    {
-      if (png_ptr->color_type == 3)
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
          int i;
-         png_byte br, bg, bb;
+         png_color back;
 
-         br = palette[png_ptr->background.index].red;
+         back.red   = (png_byte)png_ptr->background.red;
-         bg = palette[png_ptr->background.index].green;
+         back.green = (png_byte)png_ptr->background.green;
-         bb = palette[png_ptr->background.index].blue;
+         back.blue  = (png_byte)png_ptr->background.blue;
 
          for (i = 0; i < num_palette; i++)
          {
             if (i >= (int)png_ptr->num_trans ||
                png_ptr->trans[i] == 0)
             {
-               palette[i].red = br;
+               palette[i].red = back.red;
-               palette[i].green = bg;
+               palette[i].green = back.green;
-               palette[i].blue = bb;
+               palette[i].blue = back.blue;
             }
             else if (i < (int)png_ptr->num_trans ||
                png_ptr->trans[i] != 0xff)
@@ -1314,19 +1440,19 @@ png_correct_palette(png_structp png_ptr, png_colorp palette,
                palette[i].red = (png_byte)((
                   (png_uint_32)(png_ptr->palette[i].red) *
                   (png_uint_32)(png_ptr->trans[i]) +
-                  (png_uint_32)(br) *
+                  (png_uint_32)(back.red) *
                   (png_uint_32)(255 - png_ptr->trans[i]) +
                   127) / 255);
                palette[i].green = (png_byte)((
                   (png_uint_32)(png_ptr->palette[i].green) *
                   (png_uint_32)(png_ptr->trans[i]) +
-                  (png_uint_32)(bg) *
+                  (png_uint_32)(back.green) *
                   (png_uint_32)(255 - png_ptr->trans[i]) +
                   127) / 255);
                palette[i].blue = (png_byte)((
                   (png_uint_32)(png_ptr->palette[i].blue) *
                   (png_uint_32)(png_ptr->trans[i]) +
-                  (png_uint_32)(bb) *
+                  (png_uint_32)(back.blue) *
                   (png_uint_32)(255 - png_ptr->trans[i]) +
                   127) / 255);
             }
@@ -1340,20 +1466,21 @@ png_correct_palette(png_structp png_ptr, png_colorp palette,
          {
             if (i == (int)png_ptr->trans_values.gray)
             {
-               palette[i].red = (png_byte)png_ptr->background.gray;
+               palette[i].red = (png_byte)png_ptr->background.red;
-               palette[i].green = (png_byte)png_ptr->background.gray;
+               palette[i].green = (png_byte)png_ptr->background.green;
-               palette[i].blue = (png_byte)png_ptr->background.gray;
+               palette[i].blue = (png_byte)png_ptr->background.blue;
-            }
             }
          }
       }
    }
 #endif
+}
+#endif
 
 #if defined(PNG_READ_BACKGROUND_SUPPORTED)
 /* replace any alpha or transparency with the supplied background color.
-   background is the color (in rgb or grey or palette index, as
+   background is the color.  note that paletted files are taken care of
-   appropriate).  note that paletted files are taken care of elsewhere */
+   elsewhere */
 void
 png_do_background(png_row_infop row_info, png_bytep row,
    png_color_16p trans_values, png_color_16p background,
@@ -1364,8 +1491,8 @@ png_do_background(png_row_infop row_info, png_bytep row,
 {
    png_bytep sp, dp;
    png_uint_32 i;
-
    int shift;
+
    if (row && row_info && background &&
       (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
       (row_info->color_type != PNG_COLOR_TYPE_PALETTE &&
@@ -1423,7 +1550,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
                }
                case 4:
                {
-                  sp = row + 1;
+                  sp = row;
                   shift = 4;
                   for (i = 0; i < row_info->width; i++)
                   {
@@ -2013,7 +2140,7 @@ png_do_background(png_row_infop row_info, png_bytep row,
       if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
       {
          row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
-         row_info->channels -= (png_byte)1;
+         row_info->channels--;
          row_info->pixel_depth = (png_byte)(row_info->channels *
             row_info->bit_depth);
          row_info->rowbytes = ((row_info->width *

pngrutil.c

@@ -1,10 +1,10 @@
 
 /* pngrutil.c - utilities to read a png file
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -71,6 +71,9 @@ png_handle_IHDR(png_structp png_ptr, png_infop info, png_uint_32 length)
    int bit_depth, color_type, compression_type, filter_type;
    int interlace_type;
 
+   if (png_ptr->mode != PNG_BEFORE_IHDR)
+      png_error(png_ptr, "Out of place IHDR");
+
    /* check the length */
    if (length != 13)
       png_error(png_ptr, "Invalid IHDR chunk");
@@ -87,36 +90,36 @@ png_handle_IHDR(png_structp png_ptr, png_infop info, png_uint_32 length)
 
    /* check for width and height valid values */
    if (width == 0 || height == 0)
-      png_error(png_ptr, "Invalid Width or Height Found");
+      png_error(png_ptr, "Invalid image size in IHDR");
 
    /* check other values */
    if (bit_depth != 1 && bit_depth != 2 &&
       bit_depth != 4 && bit_depth != 8 &&
       bit_depth != 16)
-      png_error(png_ptr, "Invalid Bit Depth Found");
+      png_error(png_ptr, "Invalid bit depth in IHDR");
 
    if (color_type < 0 || color_type == 1 ||
       color_type == 5 || color_type > 6)
-      png_error(png_ptr, "Invalid Color Type Found");
+      png_error(png_ptr, "Invalid color type in IHDR");
 
    if (color_type == PNG_COLOR_TYPE_PALETTE &&
       bit_depth == 16)
-      png_error(png_ptr, "Found Invalid Color Type and Bit Depth Combination");
+      png_error(png_ptr, "Invalid color type and bit depth combination in IHDR");
 
    if ((color_type == PNG_COLOR_TYPE_RGB ||
       color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
       color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
       bit_depth < 8)
-      png_error(png_ptr, "Found Invalid Color Type and Bit Depth Combination");
+      png_error(png_ptr, "Invalid color type and bit depth in IHDR");
 
    if (interlace_type > 1)
-      png_error(png_ptr, "Found Invalid Interlace Value");
+      png_error(png_ptr, "Invalid interlace method in IHDR");
 
    if (compression_type > 0)
-      png_error(png_ptr, "Found Invalid Compression Value");
+      png_error(png_ptr, "Invalid compression method in IHDR");
 
    if (filter_type > 0)
-      png_error(png_ptr, "Found Invalid Filter Value");
+      png_error(png_ptr, "Invalid filter method in IHDR");
 
    /* set internal variables */
    png_ptr->width = width;
@@ -150,6 +153,8 @@ png_handle_IHDR(png_structp png_ptr, png_infop info, png_uint_32 length)
    /* call the IHDR callback (which should just set up info) */
    png_read_IHDR(png_ptr, info, width, height, bit_depth,
       color_type, compression_type, filter_type, interlace_type);
+
+   png_ptr->mode |= PNG_HAVE_IHDR;
 }
 
 /* read and check the palette */
@@ -159,8 +164,32 @@ png_handle_PLTE(png_structp png_ptr, png_infop info, png_uint_32 length)
    int num, i;
    png_colorp palette;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before PLTE");
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      png_error(png_ptr, "Multiple PLTE");
+
+#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+   if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      png_crc_skip(png_ptr, length);
+      return;
+   }
+#endif
+
    if (length % 3)
-      png_error(png_ptr, "Invalid Palette Chunk");
+   {
+      if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+      {
+         png_warning(png_ptr, "Invalid palette chunk");
+         png_crc_skip(png_ptr, length);
+         return;
+      }
+      else
+      {
+         png_error(png_ptr, "Invalid palette chunk");
+      }
+   }
 
    num = (int)length / 3;
    palette = (png_colorp)png_large_malloc(png_ptr, num * sizeof (png_color));
@@ -178,6 +207,8 @@ png_handle_PLTE(png_structp png_ptr, png_infop info, png_uint_32 length)
    png_ptr->palette = palette;
    png_ptr->num_palette = (png_uint_16)num;
    png_read_PLTE(png_ptr, info, palette, num);
+
+   png_ptr->mode |= PNG_HAVE_PLTE;
 }
 
 #if defined(PNG_READ_gAMA_SUPPORTED)
@@ -188,6 +219,12 @@ png_handle_gAMA(png_structp png_ptr, png_infop info, png_uint_32 length)
    float gamma;
    png_byte buf[4];
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before gAMA");
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Out of place gAMA chunk");
+
    if (length != 4)
    {
       png_warning(png_ptr, "Incorrect gAMA chunk length");
@@ -216,6 +253,12 @@ png_handle_sBIT(png_structp png_ptr, png_infop info, png_uint_32 length)
 
    buf[0] = buf[1] = buf[2] = buf[3] = 0;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before sBIT");
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Out of place sBIT chunk");
+
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       slen = 3;
    else
@@ -253,6 +296,12 @@ png_handle_cHRM(png_structp png_ptr, png_infop info, png_uint_32 length)
    png_uint_32 v;
    float white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before sBIT");
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Missing PLTE before cHRM");
+
    if (length != 32)
    {
       png_warning(png_ptr, "Incorrect cHRM chunk length");
@@ -301,9 +350,17 @@ png_handle_cHRM(png_structp png_ptr, png_infop info, png_uint_32 length)
 void
 png_handle_tRNS(png_structp png_ptr, png_infop info, png_uint_32 length)
 {
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before tRNS");
+
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
    {
-      if (length > png_ptr->num_palette)
+      if (!(png_ptr->mode & PNG_HAVE_PLTE))
+      {
+         /* Should be an error, but we can cope with it */
+         png_warning(png_ptr, "Missing PLTE before tRNS");
+      }
+      else if (length > png_ptr->num_palette)
       {
          png_warning(png_ptr, "Incorrect tRNS chunk length");
          png_crc_skip(png_ptr, length);
@@ -348,7 +405,11 @@ png_handle_tRNS(png_structp png_ptr, png_infop info, png_uint_32 length)
       png_ptr->trans_values.gray = png_get_uint_16(buf);
    }
    else
-      png_warning(png_ptr, "Invalid tRNS chunk");
+   {
+      png_warning(png_ptr, "tRNS chunk not allowed with alpha channel");
+      png_crc_skip(png_ptr, length);
+      return;
+   }
 
    png_read_tRNS(png_ptr, info, png_ptr->trans, png_ptr->num_trans,
       &(png_ptr->trans_values));
@@ -362,6 +423,16 @@ png_handle_bKGD(png_structp png_ptr, png_infop info, png_uint_32 length)
    int truelen;
    png_byte buf[6];
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before bKGD");
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+            !(png_ptr->mode & PNG_HAVE_PLTE))
+   {
+      png_warning(png_ptr, "Missing PLTE before bKGD");
+      png_crc_skip(png_ptr, length);
+      return;
+   }
+
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       truelen = 1;
    else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
@@ -377,10 +448,24 @@ png_handle_bKGD(png_structp png_ptr, png_infop info, png_uint_32 length)
    }
 
    png_crc_read(png_ptr, buf, length);
+   /* We convert the index value into RGB components so that we can allow
+    * arbitrary RGB values for background when we have transparency, and
+    * so it is easy to determine the RGB values of the background color
+    * from the info_ptr. */
    if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
       png_ptr->background.index = buf[0];
+      png_ptr->background.red = (png_uint_16)png_ptr->palette[buf[0]].red;
+      png_ptr->background.green = (png_uint_16)png_ptr->palette[buf[0]].green;
+      png_ptr->background.blue = (png_uint_16)png_ptr->palette[buf[0]].blue;
+   }
    else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      png_ptr->background.red =
+      png_ptr->background.green =
+      png_ptr->background.blue =
       png_ptr->background.gray = png_get_uint_16(buf);
+   }
    else
    {
       png_ptr->background.red = png_get_uint_16(buf);
@@ -398,6 +483,15 @@ png_handle_hIST(png_structp png_ptr, png_infop info, png_uint_32 length)
 {
    int num, i;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before hIST");
+   else if (!(png_ptr->mode & PNG_HAVE_PLTE))
+   {
+      png_warning(png_ptr, "Missing PLTE before hIST");
+      png_crc_skip(png_ptr, length);
+      return;
+   }
+
    if (length != 2 * png_ptr->num_palette)
    {
       png_warning(png_ptr, "Incorrect hIST chunk length");
@@ -428,6 +522,9 @@ png_handle_pHYs(png_structp png_ptr, png_infop info, png_uint_32 length)
    png_uint_32 res_x, res_y;
    int unit_type;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before pHYS");
+
    if (length != 9)
    {
       png_warning(png_ptr, "Incorrect pHYs chunk length");
@@ -452,6 +549,9 @@ png_handle_oFFs(png_structp png_ptr, png_infop info, png_uint_32 length)
    png_uint_32 offset_x, offset_y;
    int unit_type;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before oFFs");
+
    if (length != 9)
    {
       png_warning(png_ptr, "Incorrect oFFs chunk length");
@@ -475,6 +575,9 @@ png_handle_tIME(png_structp png_ptr, png_infop info, png_uint_32 length)
    png_byte buf[7];
    png_time mod_time;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before tIME");
+
    if (length != 7)
    {
       png_warning(png_ptr, "Incorrect tIME chunk length");
@@ -503,12 +606,15 @@ png_handle_tEXt(png_structp png_ptr, png_infop info, png_uint_32 length)
    png_charp key;
    png_charp text;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before tEXt");
+
    key = (png_charp )png_large_malloc(png_ptr, length + 1);
    png_crc_read(png_ptr, (png_bytep )key, length);
    key[(png_size_t)length] = '\0';
 
    for (text = key; *text; text++)
-      /* empty loop */ ;
+      /* empty loop to check key length */ ;
 
    if (text != key + (png_size_t)length)
       text++;
@@ -518,15 +624,19 @@ png_handle_tEXt(png_structp png_ptr, png_infop info, png_uint_32 length)
 #endif
 
 #if defined(PNG_READ_zTXt_SUPPORTED)
-/* note: this does not correctly handle chunks that are > 64K compressed */
+/* note: this does not correctly handle chunks that are > 64K compressed
+   on those systems that can't malloc more than 64KB at a time. */
 void
 png_handle_zTXt(png_structp png_ptr, png_infop info, png_uint_32 length)
 {
+   static char msg[] = "Error decoding zTXt chunk";
    png_charp key;
    png_charp text;
-   int ret;
    png_uint_32 text_size, key_size;
 
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before zTXt");
+
    key = png_large_malloc(png_ptr, length + 1);
    png_crc_read(png_ptr, (png_bytep )key, length);
    key[(png_size_t)length] = '\0';
@@ -538,18 +648,19 @@ png_handle_zTXt(png_structp png_ptr, png_infop info, png_uint_32 length)
    if (text == key + (png_size_t)length)
    {
       png_warning(png_ptr, "Zero length zTXt chunk");
-      png_large_free(png_ptr, key);
+      text_size = 0;
-      return;
    }
-
+   else if (*(++text)) /* check compression type byte */
-   text++;
-
-   if (*text) /* check compression byte */
    {
-      png_large_free(png_ptr, key);
+      png_warning(png_ptr, "Unknown zTXt compression type");
-      return;
-   }
 
+      /* Copy what we can of the error message into the text chunk */
+      text_size = length - (text - key) - 1;
+      text_size = sizeof(msg) > text_size ? text_size : sizeof(msg);
+      png_memcpy(text, msg, (png_size_t)(text_size + 1));
+   }
+   else
+   {
       text++;
 
       png_ptr->zstream->next_in = (png_bytep )text;
@@ -560,10 +671,11 @@ png_handle_zTXt(png_structp png_ptr, png_infop info, png_uint_32 length)
       key_size = text - key;
       text_size = 0;
       text = NULL;
-   ret = Z_STREAM_END;
 
       while (png_ptr->zstream->avail_in)
       {
+         int ret;
+
          ret = inflate(png_ptr->zstream, Z_PARTIAL_FLUSH);
          if (ret != Z_OK && ret != Z_STREAM_END)
          {
@@ -573,9 +685,21 @@ png_handle_zTXt(png_structp png_ptr, png_infop info, png_uint_32 length)
                png_warning(png_ptr, "zTXt decompression error");
             inflateReset(png_ptr->zstream);
             png_ptr->zstream->avail_in = 0;
-         png_large_free(png_ptr, key);
+
-         png_large_free(png_ptr, text);
+            if (!text)
-         return;
+            {
+               text_size = key_size + sizeof(msg) + 1;
+               text = (png_charp)png_large_malloc(png_ptr, text_size);
+               png_memcpy(text, key, (png_size_t)key_size);
+            }
+
+            text[text_size - 1] = '\0';
+
+            /* Copy what we can of the error message into the text chunk */
+            text_size = length - (text - key) - 1;
+            text_size = sizeof(msg) > text_size ? text_size : sizeof(msg);
+            png_memcpy(text + key_size, msg, (png_size_t)(text_size + 1));
+            break;
          }
          if (!png_ptr->zstream->avail_out || ret == Z_STREAM_END)
          {
@@ -610,30 +734,21 @@ png_handle_zTXt(png_structp png_ptr, png_infop info, png_uint_32 length)
                png_ptr->zstream->next_out = png_ptr->zbuf;
                png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
             }
-      }
             else
             {
                break;
             }
-
+         }
-      if (ret == Z_STREAM_END)
-         break;
       }
 
       inflateReset(png_ptr->zstream);
       png_ptr->zstream->avail_in = 0;
 
-   if (ret != Z_STREAM_END)
-   {
-      png_large_free(png_ptr, key);
-      png_large_free(png_ptr, text);
-      return;
-   }
-
       png_large_free(png_ptr, key);
       key = text;
       text += (png_size_t)key_size;
       text_size -= key_size;
+   }
 
    png_read_zTXt(png_ptr, info, key, text, text_size, 0);
 }
@@ -964,7 +1079,7 @@ png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass)
 #endif
 
 void
-png_read_filter_row(png_row_infop row_info, png_bytep row,
+png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep row,
    png_bytep prev_row, int filter)
 {
    switch (filter)
@@ -1064,6 +1179,7 @@ png_read_filter_row(png_row_infop row_info, png_bytep row,
          break;
       }
       default:
+         png_error(png_ptr, "Bad adaptive filter type");
          break;
    }
 }
@@ -1107,7 +1223,7 @@ png_read_finish_row(png_structp png_ptr)
          return;
    }
 
-   if (!png_ptr->zlib_finished)
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
    {
       char extra;
       int ret;
@@ -1127,7 +1243,7 @@ png_read_finish_row(png_structp png_ptr)
                crc = png_get_uint_32(buf);
                if (((crc ^ 0xffffffffL) & 0xffffffffL) !=
                   (png_ptr->crc & 0xffffffffL))
-                  png_error(png_ptr, "Bad CRC value");
+                  png_warning(png_ptr, "Bad CRC value");
 
                png_read_data(png_ptr, buf, 4);
                png_ptr->idat_size = png_get_uint_32(buf);
@@ -1151,11 +1267,12 @@ png_read_finish_row(png_structp png_ptr)
             if (!(png_ptr->zstream->avail_out) || png_ptr->zstream->avail_in ||
                png_ptr->idat_size)
                png_error(png_ptr, "Extra compressed data");
-            png_ptr->mode = PNG_AT_LAST_IDAT;
+            png_ptr->mode |= PNG_AT_LAST_IDAT;
             break;
          }
          if (ret != Z_OK)
-            png_error(png_ptr, "Compression Error");
+            png_error(png_ptr, png_ptr->zstream->msg ? png_ptr->zstream->msg :
+                      "Decompression Error");
 
          if (!(png_ptr->zstream->avail_out))
             png_error(png_ptr, "Extra compressed data");
@@ -1169,7 +1286,7 @@ png_read_finish_row(png_structp png_ptr)
 
    inflateReset(png_ptr->zstream);
 
-   png_ptr->mode = PNG_AT_LAST_IDAT;
+   png_ptr->mode |= PNG_AT_LAST_IDAT;
 }
 
 void
@@ -1206,13 +1323,11 @@ png_read_start_row(png_structp png_ptr)
 
 #if defined(PNG_READ_PACK_SUPPORTED)
    if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
-   {
       max_pixel_depth = 8;
-   }
 #endif
 
-#if defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_PACK_SUPPORTED)
+#if defined(PNG_READ_EXPAND_SUPPORTED)
-   if (png_ptr->transformations & (PNG_EXPAND | PNG_PACK))
+   if (png_ptr->transformations & PNG_EXPAND)
    {
       if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
       {
@@ -1277,19 +1392,18 @@ png_read_start_row(png_structp png_ptr)
       1 + ((max_pixel_depth + 7) >> 3);
 #ifdef PNG_MAX_MALLOC_64K
    if (rowbytes > 65536L)
-      png_error(png_ptr, "This image requires a row greater then 64KB");
+      png_error(png_ptr, "This image requires a row greater than 64KB");
 #endif
    png_ptr->row_buf = (png_bytep )png_large_malloc(png_ptr, rowbytes);
 
 #ifdef PNG_MAX_MALLOC_64K
    if (png_ptr->rowbytes + 1 > 65536L)
-      png_error(png_ptr, "This image requires a row greater then 64KB");
+      png_error(png_ptr, "This image requires a row greater than 64KB");
 #endif
-   png_ptr->prev_row = png_large_malloc(png_ptr,
+   png_ptr->prev_row = png_large_malloc(png_ptr, png_ptr->rowbytes + 1);
-      png_ptr->rowbytes + 1);
 
    png_memset(png_ptr->prev_row, 0, (png_size_t)png_ptr->rowbytes + 1);
 
-   png_ptr->row_init = 1;
+   png_ptr->flags |= PNG_FLAG_ROW_INIT;
 }
 

pngtest.c

@@ -1,9 +1,9 @@
 /* pngtest.c - a simple test program to test libpng
 
-   libpng 1.0 beta 2 - version 0.87
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 15, 1996
+   May 25, 1996
 */
 
 #include <stdio.h>
@@ -19,27 +19,31 @@
 #define STDERR stdout   /* for DOS */
 
 /* input and output filenames */
-char inname[] = "pngtest.png";
+#ifdef RISCOS
-char outname[] = "pngout.png";
+char *inname = "pngtest_pn";
-
+char *outname = "pngout_png";
-png_struct read_ptr;
+#else
-png_struct write_ptr;
+char *inname = "pngtest.png";
-png_info info_ptr;
+char *outname = "pngout.png";
-png_info end_info;
+#endif
 
 char inbuf[256], outbuf[256];
 
-int main()
+int main(int argc, char *argv[])
 {
    FILE *fpin, *fpout;
+   png_structp read_ptr;
+   png_structp write_ptr;
+   png_infop info_ptr;
+   png_infop end_info;
    png_bytep row_buf;
    png_byte *near_row_buf;
    png_uint_32 rowbytes;
    png_uint_32 y;
    int channels, num_pass, pass;
 
-   row_buf = (png_bytep)0;
+   row_buf = (png_bytep)NULL;
-   near_row_buf = (png_byte *)0;
+   near_row_buf = (png_byte *)NULL;
 
    fprintf(STDERR, "Testing libpng version %s\n", PNG_LIBPNG_VER_STRING);
 
@@ -51,6 +55,18 @@ int main()
       fprintf(STDERR, "  png.c version: %s\n\n", png_libpng_ver);
    }
 
+   if (argc > 1)
+     inname = argv[1];
+
+   if (argc > 2)
+     outname = argv[2];
+
+   if (argc > 3)
+   {
+     fprintf(stderr, "usage: %s [infile.png] [outfile.png]\n", argv[0]);
+     exit(1);
+   }
+
    fpin = fopen(inname, "rb");
    if (!fpin)
    {
@@ -61,62 +77,68 @@ int main()
    fpout = fopen(outname, "wb");
    if (!fpout)
    {
-      fprintf(STDERR, "could not open output file %s\n", outname);
+      fprintf(STDERR, "Could not open output file %s\n", outname);
       fclose(fpin);
       return 1;
    }
 
-   if (setjmp(read_ptr.jmpbuf))
+   read_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, (void *)NULL,
+      (png_error_ptr)NULL,  (png_error_ptr)NULL);
+   write_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, (void *)NULL,
+      (png_error_ptr)NULL, (png_error_ptr)NULL);
+   info_ptr = png_create_info_struct(read_ptr);
+   end_info = png_create_info_struct(read_ptr);
+
+   if (setjmp(read_ptr->jmpbuf))
    {
       fprintf(STDERR, "libpng read error\n");
+      png_destroy_read_struct(&read_ptr, &info_ptr, &end_info);
+      png_destroy_write_struct(&write_ptr, (png_infopp)NULL);
       fclose(fpin);
       fclose(fpout);
       return 1;
    }
 
-   if (setjmp(write_ptr.jmpbuf))
+   if (setjmp(write_ptr->jmpbuf))
    {
       fprintf(STDERR, "libpng write error\n");
+      png_destroy_read_struct(&read_ptr, &info_ptr, &end_info);
+      png_destroy_write_struct(&write_ptr, (png_infopp)NULL);
       fclose(fpin);
       fclose(fpout);
       return 1;
    }
 
-   png_read_init(&read_ptr);
+   png_init_io(read_ptr, fpin);
-   png_write_init(&write_ptr);
+   png_init_io(write_ptr, fpout);
-   png_info_init(&info_ptr);
-   png_info_init(&end_info);
 
-   png_init_io(&read_ptr, fpin);
+   png_read_info(read_ptr, info_ptr);
-   png_init_io(&write_ptr, fpout);
+   png_write_info(write_ptr, info_ptr);
 
-   png_read_info(&read_ptr, &info_ptr);
+   if ((info_ptr->color_type & PNG_COLOR_TYPE_PALETTE)==PNG_COLOR_TYPE_PALETTE)
-   png_write_info(&write_ptr, &info_ptr);
-
-   if ((info_ptr.color_type & 3) == 2)
-      channels = 3;
-   else
       channels = 1;
-   if (info_ptr.color_type & 4)
+   else
+      channels = 3;
+   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
       channels++;
 
-   rowbytes = ((info_ptr.width * info_ptr.bit_depth * channels + 7) >> 3);
+   rowbytes = ((info_ptr->width * info_ptr->bit_depth * channels + 7) >> 3);
    near_row_buf = (png_byte *)malloc((size_t)rowbytes);
    row_buf = (png_bytep)near_row_buf;
    if (!row_buf)
    {
-      fprintf(STDERR, "no memory to allocate row buffer\n");
+      fprintf(STDERR, "No memory to allocate row buffer\n");
-      png_read_destroy(&read_ptr, &info_ptr, (png_infop )0);
+      png_destroy_read_struct(&read_ptr, &info_ptr, &end_info);
-      png_write_destroy(&write_ptr);
+      png_destroy_write_struct(&write_ptr, (png_infopp)NULL);
       fclose(fpin);
       fclose(fpout);
       return 1;
    }
 
-   if (info_ptr.interlace_type)
+   if (info_ptr->interlace_type)
    {
-      num_pass = png_set_interlace_handling(&read_ptr);
+      num_pass = png_set_interlace_handling(read_ptr);
-      num_pass = png_set_interlace_handling(&write_ptr);
+      num_pass = png_set_interlace_handling(write_ptr);
    }
    else
    {
@@ -125,21 +147,21 @@ int main()
 
    for (pass = 0; pass < num_pass; pass++)
    {
-      for (y = 0; y < info_ptr.height; y++)
+      for (y = 0; y < info_ptr->height; y++)
       {
 #ifdef TESTING
          fprintf(STDERR, "Processing line #%ld\n", y);
 #endif
-         png_read_rows(&read_ptr, (png_bytepp)&row_buf, (png_bytepp)0, 1);
+         png_read_rows(read_ptr, (png_bytepp)&row_buf, (png_bytepp)0, 1);
-         png_write_rows(&write_ptr, (png_bytepp)&row_buf, 1);
+         png_write_rows(write_ptr, (png_bytepp)&row_buf, 1);
       }
    }
 
-   png_read_end(&read_ptr, &end_info);
+   png_read_end(read_ptr, end_info);
-   png_write_end(&write_ptr, &end_info);
+   png_write_end(write_ptr, end_info);
 
-   png_read_destroy(&read_ptr, &info_ptr, &end_info);
+   png_destroy_read_struct(&read_ptr, &info_ptr, &end_info);
-   png_write_destroy(&write_ptr);
+   png_destroy_write_struct(&write_ptr, (png_infopp)NULL);
 
    fclose(fpin);
    fclose(fpout);
@@ -150,14 +172,14 @@ int main()
 
    if (!fpin)
    {
-      fprintf(STDERR, "could not find file %s\n", inname);
+      fprintf(STDERR, "Could not find file %s\n", inname);
       return 1;
    }
 
    fpout = fopen(outname, "rb");
    if (!fpout)
    {
-      fprintf(STDERR, "could not find file %s\n", outname);
+      fprintf(STDERR, "Could not find file %s\n", outname);
       fclose(fpin);
       return 1;
    }
@@ -171,7 +193,8 @@ int main()
 
       if (num_in != num_out)
       {
-         fprintf(STDERR, "files are of a different size\n");
+         fprintf(STDERR, "Files %s and %s are of a different size\n",
+                 inname, outname);
          fclose(fpin);
          fclose(fpout);
          return 1;
@@ -182,7 +205,7 @@ int main()
 
       if (memcmp(inbuf, outbuf, num_in))
       {
-         fprintf(STDERR, "files are different\n");
+         fprintf(STDERR, "Files %s and %s are different\n", inname, outname);
          fclose(fpin);
          fclose(fpout);
          return 1;

pngtodo.txt

@@ -8,6 +8,8 @@ for 0.9
 
 after 1.0
    overlaying one image on top of another
+   make pull reader use push reader internally to reduce code, and
+      increase amount of image read in an error situation
    optional palette creation
    histogram creation
    text conversion between different code types

pngtrans.c

@@ -2,10 +2,10 @@
 /* pngtrans.c - transforms the data in a row
    routines used by both readers and writers
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -72,7 +72,11 @@ png_set_filler(png_structp png_ptr, int filler, int filler_loc)
 {
    png_ptr->transformations |= PNG_FILLER;
    png_ptr->filler = (png_byte)filler;
-   png_ptr->filler_loc = (png_byte)filler_loc;
+   if (filler_loc == PNG_FILLER_AFTER)
+      png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
+   else
+      png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
+
    if (png_ptr->color_type == PNG_COLOR_TYPE_RGB &&
       png_ptr->bit_depth == 8)
       png_ptr->usr_channels = 4;

pngwio.c

@@ -0,0 +1,174 @@
+
+/* pngwio.c - functions for data output
+
+   libpng 1.0 beta 3 - version 0.89
+   For conditions of distribution and use, see copyright notice in png.h
+   Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+   May 25, 1996
+
+   This file provides a location for all output.  Users which need
+   special handling are expected to write functions which have the same
+   arguments as these, and perform similar functions, but possibly use
+   different output methods.  Note that you shouldn't change these
+   functions, but rather write replacement functions and then change
+   them at run time with png_set_write_fn(...) */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+/* Write the data to whatever output you are using.  The default routine
+   writes to a file pointer.  Note that this routine sometimes gets called
+   with very small lengths, so you should implement some kind of simple
+   buffering if you are using unbuffered writes.  This should never be asked
+   to write more then 64K on a 16 bit machine.  The cast to png_size_t is
+   there to quiet warnings of certain compilers. */
+
+void
+png_write_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
+{
+   if (png_ptr->write_data_fn)
+      (*(png_ptr->write_data_fn))(png_ptr, data, length);
+   else
+      png_error(png_ptr, "Call to NULL write function");
+}
+
+/* This is the function which does the actual writing of data.  If you are
+   not writing to a standard C stream, you should create a replacement
+   write_data function and use it at run time with png_set_write_fn(), rather
+   than changing the library. */
+#ifndef USE_FAR_KEYWORD
+static void
+png_default_write_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
+{
+   png_uint_32 check;
+
+   check = fwrite(data, 1, (png_size_t)length, (FILE *)(png_ptr->io_ptr));
+   if (check != length)
+   {
+      png_error(png_ptr, "Write Error");
+   }
+}
+#else
+/* this is the model-independent version. Since the standard I/O library
+   can't handle far buffers in the medium and small models, we have to copy
+   the data.
+*/
+
+#define NEAR_BUF_SIZE 1024
+#define MIN(a,b) (a <= b ? a : b)
+
+#ifdef _MSC_VER
+/* for FP_OFF */
+#include <dos.h>
+#endif
+
+static void
+png_default_write_data(png_structp png_ptr, png_bytep data, png_uint_32 length)
+{
+   png_uint_32 check;
+   png_byte *n_data;
+
+   /* Check if data really is near. If so, use usual code. */
+#ifdef _MSC_VER
+   /* do it this way just to quiet warning */
+   FP_OFF(n_data) = FP_OFF(data);
+   if (FP_SEG(n_data) == FP_SEG(data))
+#else
+   /* this works in MSC also but with lost segment warning */
+   n_data = (png_byte *)data;
+   if ((png_bytep)n_data == data)
+#endif
+   {
+      check = fwrite(n_data, 1, (png_size_t)length, (FILE *)(png_ptr->io_ptr));
+   }
+   else
+   {
+      png_byte buf[NEAR_BUF_SIZE];
+      png_size_t written, remaining, err;
+      check = 0;
+      remaining = (png_size_t)length;
+      do
+      {
+         written = MIN(NEAR_BUF_SIZE, remaining);
+         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
+         err = fwrite(buf, 1, written, (FILE *)(png_ptr->io_ptr));
+         if (err != written)
+            break;
+         else
+            check += err;
+         data += written;
+         remaining -= written;
+      }
+      while (remaining != 0);
+   }
+   if (check != length)
+   {
+      png_error(png_ptr, "Write Error");
+   }
+}
+
+#endif
+
+/* This function is called to output any data pending writing (normally
+   to disk).  After png_flush is called, there should be no data pending
+   writing in any buffers. */
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+void
+png_flush(png_structp png_ptr)
+{
+   if (png_ptr->output_flush_fn)
+      (*(png_ptr->output_flush_fn))(png_ptr);
+}
+
+static void
+png_default_flush(png_structp png_ptr)
+{
+   if ((FILE *)(png_ptr->io_ptr))
+      fflush((FILE *)(png_ptr->io_ptr));
+}
+#endif
+
+/* This function allows the application to supply new output functions for
+   libpng if standard C streams aren't being used.
+
+   This function takes as its arguments:
+   png_ptr       - pointer to a png output data structure
+   io_ptr        - pointer to user supplied structure containing info about
+                   the output functions.  May be NULL.
+   write_data_fn - pointer to a new output function which takes as its
+                   arguments a pointer to a png_struct, a pointer to
+                   data to be written, and a 32-bit unsigned int which is
+                   the number of bytes to be written.  The new write
+                   function should call png_error(png_ptr, "Error msg")
+                   to exit and output any fatal error messages.
+   flush_data_fn - pointer to a new flush function which takes as its
+                   arguments a pointer to a png_struct.  After a call to
+                   the flush function, there should be no data in any buffers
+                   or pending transmission.  If the output method doesn't do
+                   any buffering of ouput, a function prototype must still be
+                   supplied although it doesn't have to do anything.  If
+                   PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
+                   time, output_flush_fn will be ignored, although it must be
+                   supplied for compatibility. */
+void
+png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
+   png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
+{
+   png_ptr->io_ptr = io_ptr;
+
+   if (write_data_fn)
+      png_ptr->write_data_fn = write_data_fn;
+   else
+      png_ptr->write_data_fn = png_default_write_data;
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+   if (output_flush_fn)
+      png_ptr->output_flush_fn = output_flush_fn;
+   else
+      png_ptr->output_flush_fn = png_default_flush;
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+
+   /* It is an error to read while writing a png file */
+   png_ptr->read_data_fn = NULL;
+}
+

pngwrite.c

@@ -1,10 +1,10 @@
 
 /* pngwrite.c - general routines to write a png file
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 /* get internal access to png.h */
@@ -48,6 +48,8 @@ png_write_info(png_structp png_ptr, png_infop info)
 #endif
    if (info->valid & PNG_INFO_PLTE)
       png_write_PLTE(png_ptr, info->palette, info->num_palette);
+   else if (info->color_type == PNG_COLOR_TYPE_PALETTE)
+      png_error(png_ptr, "Valid palette required for paletted images\n");
 #if defined(PNG_WRITE_tRNS_SUPPORTED)
    if (info->valid & PNG_INFO_tRNS)
       png_write_tRNS(png_ptr, info->trans, &(info->trans_values),
@@ -73,10 +75,13 @@ png_write_info(png_structp png_ptr, png_infop info)
 #endif
 #if defined(PNG_WRITE_tIME_SUPPORTED)
    if (info->valid & PNG_INFO_tIME)
+   {
       png_write_tIME(png_ptr, &(info->mod_time));
-   /* Check to see if we need to write text chunks */
+      png_ptr->flags |= PNG_FLAG_WROTE_tIME;
+   }
 #endif
 #if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
+   /* Check to see if we need to write text chunks */
    if (info->num_text)
    {
       int i; /* local counter */
@@ -92,6 +97,8 @@ png_write_info(png_structp png_ptr, png_infop info)
             png_write_zTXt(png_ptr, info->text[i].key,
                info->text[i].text, info->text[i].text_length,
                info->text[i].compression);
+#else
+            png_warning(png_ptr, "Unable to write compressed text\n");
 #endif
          }
          else
@@ -100,6 +107,8 @@ png_write_info(png_structp png_ptr, png_infop info)
             /* write uncompressed chunk */
             png_write_tEXt(png_ptr, info->text[i].key,
                info->text[i].text, info->text[i].text_length);
+#else
+            png_warning(png_ptr, "Unable to write uncompressed text\n");
 #endif
          }
       }
@@ -114,12 +123,16 @@ png_write_info(png_structp png_ptr, png_infop info)
 void
 png_write_end(png_structp png_ptr, png_infop info)
 {
+   if (!(png_ptr->mode & PNG_HAVE_IDAT))
+      png_error(png_ptr, "No IDATs written into file");
+
    /* see if user wants us to write information chunks */
    if (info)
    {
 #if defined(PNG_WRITE_tIME_SUPPORTED)
       /* check to see if user has supplied a time chunk */
-      if (info->valid & PNG_INFO_tIME)
+      if (info->valid & PNG_INFO_tIME &&
+         !(png_ptr->flags & PNG_FLAG_WROTE_tIME))
          png_write_tIME(png_ptr, &(info->mod_time));
 #endif
 #if defined(PNG_WRITE_tEXt_SUPPORTED) || defined(PNG_WRITE_zTXt_SUPPORTED)
@@ -131,28 +144,33 @@ png_write_end(png_structp png_ptr, png_infop info)
          /* loop through comment chunks */
          for (i = 0; i < info->num_text; i++)
          {
+#if defined(PNG_WRITE_zTXt_SUPPORTED)
             /* check to see if comment is to be compressed */
             if (info->text[i].compression >= 0)
             {
-#if defined(PNG_WRITE_zTXt_SUPPORTED)
                /* write compressed chunk */
                png_write_zTXt(png_ptr, info->text[i].key,
                   info->text[i].text, info->text[i].text_length,
                   info->text[i].compression);
-#endif
             }
-            else
-            {
 #if defined(PNG_WRITE_tEXt_SUPPORTED)
+            else
+#endif
+#endif
+#if defined(PNG_WRITE_tEXt_SUPPORTED)
+            {
                /* write uncompressed chunk */
                png_write_tEXt(png_ptr, info->text[i].key,
                   info->text[i].text, info->text[i].text_length);
-#endif
             }
+#endif
          }
       }
 #endif
    }
+
+   png_ptr->mode |= PNG_AFTER_IDAT;
+
    /* write end of png file */
    png_write_IEND(png_ptr);
 }
@@ -180,31 +198,70 @@ png_convert_from_time_t(png_timep ptime, time_t ttime)
 #endif
 
 /* initialize png structure, and allocate any memory needed */
-void
+png_structp
-png_write_init(png_structp png_ptr)
+png_create_write_struct(png_const_charp user_png_ver, voidp error_ptr,
+   png_error_ptr warn_fn, png_error_ptr error_fn)
 {
-   jmp_buf tmp_jmp; /* to save current jump buffer */
+   png_structp png_ptr;
-   png_msg_ptr error_fn;
-   png_msg_ptr warning_fn;
-   png_voidp msg_ptr;
 
-   /* save jump buffer and error functions */
+   if ((png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG)) == NULL)
-   png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
+   {
-   error_fn = png_ptr->error_fn;
+      return (png_structp)NULL;
-   warning_fn = png_ptr->warning_fn;
+   }
-   msg_ptr = png_ptr->msg_ptr;
 
-   /* reset all variables to 0 */
+   if (setjmp(png_ptr->jmpbuf))
-   png_memset(png_ptr, 0, sizeof (png_struct));
+   {
-   /* restore jump buffer and error functions */
+      png_large_free(png_ptr, png_ptr->zbuf);
-   png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
+      png_free(png_ptr, png_ptr->zstream);
-   png_ptr->error_fn = error_fn;
+      png_destroy_struct(png_ptr);
-   png_ptr->warning_fn = warning_fn;
+      return (png_structp)NULL;
-   png_ptr->msg_ptr = msg_ptr;
+   }
+
+   png_set_error_fn(png_ptr, error_ptr, warn_fn, error_fn);
+
+   if (user_png_ver == NULL || strcmp(user_png_ver, png_libpng_ver))
+   {
+      if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0])
+      {
+         png_error(png_ptr, "Incompatible libpng versions");
+      }
+      else
+      {
+         png_warning(png_ptr, "Different libpng versions");
+      }
+   }
 
    /* initialize zbuf - compression buffer */
    png_ptr->zbuf_size = PNG_ZBUF_SIZE;
    png_ptr->zbuf = png_large_malloc(png_ptr, png_ptr->zbuf_size);
+
+   png_set_write_fn(png_ptr, NULL, NULL, NULL);
+
+   png_ptr->do_free |= PNG_FREE_STRUCT;
+
+   return (png_ptr);
+}
+
+
+/* initialize png structure, and allocate any memory needed */
+void
+png_write_init(png_structp png_ptr)
+{
+   jmp_buf tmp_jmp; /* to save current jump buffer */
+
+   /* save jump buffer and error functions */
+   png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
+
+   /* reset all variables to 0 */
+   png_memset(png_ptr, 0, sizeof (png_struct));
+
+   /* restore jump buffer */
+   png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
+
+   /* initialize zbuf - compression buffer */
+   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
+   png_ptr->zbuf = png_large_malloc(png_ptr, png_ptr->zbuf_size);
+   png_set_write_fn(png_ptr, NULL, NULL, NULL);
 }
 
 /* write a few rows of image data.  If the image is interlaced,
@@ -248,7 +305,7 @@ png_write_image(png_structp png_ptr, png_bytepp image)
    }
 }
 
-/* write a row of image data */
+/* called by user to write a row of image data */
 void
 png_write_row(png_structp png_ptr, png_bytep row)
 {
@@ -350,73 +407,19 @@ png_write_row(png_structp png_ptr, png_bytep row)
    if (png_ptr->transformations)
       png_do_write_transformations(png_ptr);
 
-   /* filter rows that have been proved to help */
+   /* find a filter if necessary, filter the row and write it out */
-   if (png_ptr->do_filter)
+   png_write_find_filter(png_ptr, &(png_ptr->row_info));
+
+   /* trade current and prev rows so next filter references are correct */
+   if (png_ptr->prev_row)
    {
-      /* save row to previous row */
-      png_memcpy(png_ptr->save_row, png_ptr->row_buf,
-         (png_size_t)png_ptr->row_info.rowbytes + 1);
-
-      /* filter row */
-      png_write_filter_row(&(png_ptr->row_info), png_ptr->row_buf,
-         png_ptr->prev_row);
-
-      /* trade saved pointer and prev pointer so next row references are correctly */
-      { /* scope limiter */
       png_bytep tptr;
 
       tptr = png_ptr->prev_row;
-         png_ptr->prev_row = png_ptr->save_row;
+      png_ptr->prev_row = png_ptr->row_buf;
-         png_ptr->save_row = tptr;
+      png_ptr->row_buf = tptr;
    }
 }
-   else
-      /* set filter row to "none" */
-      png_ptr->row_buf[0] = 0;
-
-   /* set up the zlib input buffer */
-   png_ptr->zstream->next_in = png_ptr->row_buf;
-   png_ptr->zstream->avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
-   /* repeat until we have compressed all the data */
-   do
-   {
-      int ret; /* return of zlib */
-
-      /* compress the data */
-      ret = deflate(png_ptr->zstream, Z_NO_FLUSH);
-      /* check for compression errors */
-      if (ret != Z_OK)
-      {
-         if (png_ptr->zstream->msg)
-            png_error(png_ptr, png_ptr->zstream->msg);
-         else
-            png_error(png_ptr, "zlib error");
-      }
-
-      /* see if it is time to write another IDAT */
-      if (!png_ptr->zstream->avail_out)
-      {
-         /* write the IDAT and reset the zlib output buffer */
-         png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
-         png_ptr->zstream->next_out = png_ptr->zbuf;
-         png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
-      }
-   /* repeat until all data has been compressed */
-   } while (png_ptr->zstream->avail_in);
-
-   /* finish row - updates counters and flushes zlib if last row */
-   png_write_finish_row(png_ptr);
-
-#if defined(PNG_WRITE_FLUSH_SUPPORTED)
-   png_ptr->flush_rows++;
-
-   if (png_ptr->flush_dist > 0 &&
-       png_ptr->flush_rows >= png_ptr->flush_dist)
-   {
-      png_write_flush(png_ptr);
-   }
-#endif /* PNG_WRITE_FLUSH_SUPPORTED */
-}
 
 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
 /* Set the automatic flush interval or 0 to turn flushing off */
@@ -432,7 +435,8 @@ png_write_flush(png_structp png_ptr)
 {
    int wrote_IDAT;
 
-   if (png_ptr->mode != PNG_HAVE_IDAT)
+   /* We have already written out all of the data */
+   if (png_ptr->row_number >= png_ptr->num_rows)
      return;
 
    do
@@ -477,65 +481,184 @@ png_write_flush(png_structp png_ptr)
 }
 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
 
+/* free all memory used by the write */
+void
+png_destroy_write_struct(png_structpp png_ptr, png_infopp info_ptr)
+{
+   if (info_ptr && *info_ptr)
+   {
+      png_destroy_struct((voidp)*info_ptr);
+      *info_ptr = (png_infop)NULL;
+   }
 
-/* free any memory used in png struct */
+   if (png_ptr && *png_ptr)
+   {
+      png_write_destroy(*png_ptr);
+      png_destroy_struct((voidp)*png_ptr);
+      *png_ptr = (png_structp)NULL;
+   }
+}
+
+
+/* free any memory used in png struct (old) */
 void
 png_write_destroy(png_structp png_ptr)
 {
    jmp_buf tmp_jmp; /* save jump buffer */
+   png_error_ptr error_fn;
+   png_error_ptr warning_fn;
+   png_voidp error_ptr;
 
    /* free any memory zlib uses */
    deflateEnd(png_ptr->zstream);
    png_free(png_ptr, png_ptr->zstream);
+
    /* free our memory.  png_free checks NULL for us. */
    png_large_free(png_ptr, png_ptr->zbuf);
    png_large_free(png_ptr, png_ptr->row_buf);
    png_large_free(png_ptr, png_ptr->prev_row);
-   png_large_free(png_ptr, png_ptr->save_row);
+   png_large_free(png_ptr, png_ptr->sub_row);
+   png_large_free(png_ptr, png_ptr->up_row);
+   png_large_free(png_ptr, png_ptr->avg_row);
+   png_large_free(png_ptr, png_ptr->paeth_row);
+
    /* reset structure */
    png_memcpy(tmp_jmp, png_ptr->jmpbuf, sizeof (jmp_buf));
+
+   error_fn = png_ptr->error_fn;
+   warning_fn = png_ptr->warning_fn;
+   error_ptr = png_ptr->error_ptr;
+
    png_memset(png_ptr, 0, sizeof (png_struct));
+
+   png_ptr->error_fn = error_fn;
+   png_ptr->warning_fn = warning_fn;
+   png_ptr->error_ptr = error_ptr;
+
    png_memcpy(png_ptr->jmpbuf, tmp_jmp, sizeof (jmp_buf));
 }
+
+/* Allow the application to select one or more filters to use */
 void
-png_set_filtering(png_structp png_ptr, int filter)
+png_set_filter(png_structp png_ptr, int method, int filters)
 {
-   png_ptr->do_custom_filter = 1;
+   /* We allow 'method' only for future expansion of the base filter method */
-   png_ptr->do_filter = (png_byte)filter;
+   if (method == 0)
+   {
+      switch (filters & (PNG_ALL_FILTERS | 0x07))
+      {
+         case 5:
+         case 6:
+         case 7: png_warning(png_ptr, "Unknown custom row filter for method 0");
+         case 0: png_ptr->do_filter = PNG_FILTER_NONE; break;
+         case 1: png_ptr->do_filter = PNG_FILTER_SUB; break;
+         case 2: png_ptr->do_filter = PNG_FILTER_UP; break;
+         case 3: png_ptr->do_filter = PNG_FILTER_AVG; break;
+         case 4: png_ptr->do_filter = PNG_FILTER_PAETH; break;
+         default: png_ptr->do_filter = (png_byte)filters; break;
+      }
+
+      /* If we have allocated the row_buf, then we should have also allocated
+       * all of the filter buffers that have been selected.
+       */
+      if (png_ptr->row_buf)
+      {
+         if (png_ptr->do_filter & PNG_FILTER_SUB && !(png_ptr->sub_row))
+         {
+            png_ptr->sub_row = (png_bytep )png_large_malloc(png_ptr,
+               png_ptr->rowbytes + 1);
+            png_ptr->sub_row[0] = 1;  /* Set the row filter type */
+         }
+
+         if (png_ptr->do_filter & PNG_FILTER_UP && !(png_ptr->up_row))
+         {
+            if (!(png_ptr->prev_row))
+            {
+               png_warning(png_ptr, "Can't to add up filter after starting");
+               png_ptr->do_filter &= ~PNG_FILTER_UP;
+            }
+            else
+            {
+               png_ptr->up_row = (png_bytep )png_large_malloc(png_ptr,
+                  png_ptr->rowbytes + 1);
+               png_ptr->up_row[0] = 2;  /* Set the row filter type */
+            }
+         }
+
+         if (png_ptr->do_filter & PNG_FILTER_AVG && !(png_ptr->avg_row))
+         {
+            if (!(png_ptr->prev_row))
+            {
+               png_warning(png_ptr, "Can't add average filter after starting");
+               png_ptr->do_filter &= ~PNG_FILTER_AVG;
+            }
+            else
+            {
+               png_ptr->up_row = (png_bytep )png_large_malloc(png_ptr,
+                  png_ptr->rowbytes + 1);
+               png_ptr->up_row[0] = 3;  /* Set the row filter type */
+            }
+         }
+
+         if (png_ptr->do_filter & PNG_FILTER_PAETH && !(png_ptr->paeth_row))
+         {
+            if (!(png_ptr->prev_row))
+            {
+               png_warning(png_ptr, "Can't add Paeth filter after starting");
+               png_ptr->do_filter &= ~PNG_FILTER_PAETH;
+            }
+            else
+            {
+               png_ptr->paeth_row = (png_bytep )png_large_malloc(png_ptr,
+                  png_ptr->rowbytes + 1);
+               png_ptr->paeth_row[0] = 4;  /* Set the row filter type */
+            }
+         }
+
+         if (png_ptr->do_filter == PNG_NO_FILTERS)
+            png_ptr->do_filter = PNG_FILTER_NONE;
+      }
+   }
+   else
+     png_error(png_ptr, "Unknown custom filter method");
 }
 
 void
 png_set_compression_level(png_structp png_ptr, int level)
 {
-   png_ptr->zlib_custom_level = 1;
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;
    png_ptr->zlib_level = level;
 }
 
 void
 png_set_compression_mem_level(png_structp png_ptr, int mem_level)
 {
-   png_ptr->zlib_custom_mem_level = 1;
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;
    png_ptr->zlib_mem_level = mem_level;
 }
 
 void
 png_set_compression_strategy(png_structp png_ptr, int strategy)
 {
-   png_ptr->zlib_custom_strategy = 1;
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
    png_ptr->zlib_strategy = strategy;
 }
 
 void
 png_set_compression_window_bits(png_structp png_ptr, int window_bits)
 {
-   png_ptr->zlib_custom_window_bits = 1;
+   if (window_bits > 15)
+      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;
    png_ptr->zlib_window_bits = window_bits;
 }
 
 void
 png_set_compression_method(png_structp png_ptr, int method)
 {
-   png_ptr->zlib_custom_method = 1;
+   if (method != 8)
+      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;
    png_ptr->zlib_method = method;
 }
 

pngwtran.c

@@ -1,10 +1,10 @@
 
 /* pngwtran.c - transforms the data in a row for png writers
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 
 #define PNG_INTERNAL
@@ -18,7 +18,7 @@ png_do_write_transformations(png_structp png_ptr)
 #if defined(PNG_WRITE_FILLER_SUPPORTED)
    if (png_ptr->transformations & PNG_FILLER)
       png_do_write_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
-         png_ptr->filler_loc);
+         png_ptr->flags);
 #endif
 #if defined(PNG_WRITE_PACK_SUPPORTED)
    if (png_ptr->transformations & PNG_PACK)
@@ -299,12 +299,12 @@ png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
 /* remove filler byte */
 void
 png_do_write_filler(png_row_infop row_info, png_bytep row,
-   png_byte filler_loc)
+   png_byte flags)
 {
    if (row && row_info && row_info->color_type == PNG_COLOR_TYPE_RGB &&
       row_info->bit_depth == 8)
    {
-      if (filler_loc == PNG_FILLER_AFTER)
+      if (flags & PNG_FLAG_FILLER_AFTER)
       {
          png_bytep sp, dp;
 

pngwutil.c

@@ -1,10 +1,10 @@
 
 /* pngwutil.c - utilities to write a png file
 
-   libpng 1.0 beta 2 - version 0.88
+   libpng 1.0 beta 3 - version 0.89
    For conditions of distribution and use, see copyright notice in png.h
    Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
-   January 25, 1996
+   May 25, 1996
    */
 #define PNG_INTERNAL
 #include "png.h"
@@ -139,6 +139,81 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
 {
    png_byte buf[13]; /* buffer to store the IHDR info */
 
+   /* Check that we have valid input data from the application info */
+   switch (color_type)
+   {
+      case 0:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8:
+            case 16: png_ptr->channels = 1; break;
+            default: png_error(png_ptr, "Invalid bit depth for grayscale image");
+         }
+         break;
+      case 2:
+         if (bit_depth != 8 && bit_depth != 16)
+            png_error(png_ptr, "Invalid bit depth for RGB image");
+         png_ptr->channels = 3;
+         break;
+      case 3:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8: png_ptr->channels = 1; break;
+            default: png_error(png_ptr, "Invalid bit depth for paletted image");
+         }
+         break;
+      case 4:
+         if (bit_depth != 8 && bit_depth != 16)
+            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
+         png_ptr->channels = 2;
+         break;
+      case 6:
+         if (bit_depth != 8 && bit_depth != 16)
+            png_error(png_ptr, "Invalid bit depth for RGBA image");
+         png_ptr->channels = 4;
+         break;
+      default:
+         png_error(png_ptr, "Invalid image color type specified");
+   }
+
+   if (compression_type != 0)
+   {
+      png_warning(png_ptr, "Invalid compression type specified");
+      compression_type = 0;
+   }
+
+   if (filter_type != 0)
+   {
+      png_warning(png_ptr, "Invalid filter type specified");
+      filter_type = 0;
+   }
+
+   if (interlace_type != 0 && interlace_type != 1)
+   {
+      png_warning(png_ptr, "Invalid interlace type specified");
+      interlace_type = 1;
+   }
+
+   /* save off the relevent information */
+   png_ptr->bit_depth = (png_byte)bit_depth;
+   png_ptr->color_type = (png_byte)color_type;
+   png_ptr->interlaced = (png_byte)interlace_type;
+   png_ptr->width = width;
+   png_ptr->height = height;
+
+   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+   png_ptr->rowbytes = ((width * (png_uint_32)png_ptr->pixel_depth + 7) >> 3);
+   /* set the usr info, so any transformations can modify it */
+   png_ptr->usr_width = png_ptr->width;
+   png_ptr->usr_bit_depth = png_ptr->bit_depth;
+   png_ptr->usr_channels = png_ptr->channels;
+
    /* pack the header information into the buffer */
    png_save_uint_32(buf, width);
    png_save_uint_32(buf + 4, height);
@@ -147,35 +222,6 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
    buf[10] = (png_byte)compression_type;
    buf[11] = (png_byte)filter_type;
    buf[12] = (png_byte)interlace_type;
-   /* save off the relevent information */
-   png_ptr->bit_depth = (png_byte)bit_depth;
-   png_ptr->color_type = (png_byte)color_type;
-   png_ptr->interlaced = (png_byte)interlace_type;
-   png_ptr->width = width;
-   png_ptr->height = height;
-
-   switch (color_type)
-   {
-      case 0:
-      case 3:
-         png_ptr->channels = 1;
-         break;
-      case 2:
-         png_ptr->channels = 3;
-         break;
-      case 4:
-         png_ptr->channels = 2;
-         break;
-      case 6:
-         png_ptr->channels = 4;
-         break;
-   }
-   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
-   png_ptr->rowbytes = ((width * (png_uint_32)png_ptr->pixel_depth + 7) >> 3);
-   /* set the usr info, so any transformations can modify it */
-   png_ptr->usr_width = png_ptr->width;
-   png_ptr->usr_bit_depth = png_ptr->bit_depth;
-    png_ptr->usr_channels = png_ptr->channels;
 
    /* write the chunk */
    png_write_chunk(png_ptr, png_IHDR, buf, (png_uint_32)13);
@@ -185,27 +231,27 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
    png_ptr->zstream->zalloc = png_zalloc;
    png_ptr->zstream->zfree = png_zfree;
    png_ptr->zstream->opaque = (voidpf)png_ptr;
-   if (!png_ptr->do_custom_filter)
+   if (!(png_ptr->do_filter))
    {
       if (png_ptr->color_type == 3 || png_ptr->bit_depth < 8)
-         png_ptr->do_filter = 0;
+         png_ptr->do_filter = PNG_FILTER_NONE;
       else
-         png_ptr->do_filter = 1;
+         png_ptr->do_filter = PNG_ALL_FILTERS;
    }
-   if (!png_ptr->zlib_custom_strategy)
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
    {
-      if (png_ptr->do_filter)
+      if (png_ptr->do_filter != PNG_FILTER_NONE)
          png_ptr->zlib_strategy = Z_FILTERED;
       else
          png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
    }
-   if (!png_ptr->zlib_custom_level)
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
       png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
-   if (!png_ptr->zlib_custom_mem_level)
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
       png_ptr->zlib_mem_level = 8;
-   if (!png_ptr->zlib_custom_window_bits)
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
       png_ptr->zlib_window_bits = 15;
-   if (!png_ptr->zlib_custom_method)
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
       png_ptr->zlib_method = 8;
    deflateInit2(png_ptr->zstream, png_ptr->zlib_level,
       png_ptr->zlib_method,
@@ -215,6 +261,7 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
    png_ptr->zstream->next_out = png_ptr->zbuf;
    png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
 
+   png_ptr->mode = PNG_HAVE_IHDR;
 }
 
 /* write the palette.  We are careful not to trust png_color to be in the
@@ -227,6 +274,21 @@ png_write_PLTE(png_structp png_ptr, png_colorp palette, int number)
    png_colorp pal_ptr;
    png_byte buf[3];
 
+   if (number == 0 || number > 256)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_error(png_ptr, "Invalid number of colors in palette");
+      }
+      else
+      {
+         png_warning(png_ptr, "Invalid number of colors in palette");
+         return;
+      }
+   }
+
+   png_ptr->num_palette = number;
+
    png_write_chunk_start(png_ptr, png_PLTE, number * 3);
    for (i = 0, pal_ptr = palette;
       i < number;
@@ -238,6 +300,7 @@ png_write_PLTE(png_structp png_ptr, png_colorp palette, int number)
       png_write_chunk_data(png_ptr, buf, (png_uint_32)3);
    }
    png_write_chunk_end(png_ptr);
+   png_ptr->mode |= PNG_HAVE_PLTE;
 }
 
 /* write an IDAT chunk */
@@ -245,6 +308,7 @@ void
 png_write_IDAT(png_structp png_ptr, png_bytep data, png_uint_32 length)
 {
    png_write_chunk(png_ptr, png_IDAT, data, length);
+   png_ptr->mode |= PNG_HAVE_IDAT;
 }
 
 /* write an IEND chunk */
@@ -252,6 +316,7 @@ void
 png_write_IEND(png_structp png_ptr)
 {
    png_write_chunk(png_ptr, png_IEND, NULL, (png_uint_32)0);
+   png_ptr->mode |= PNG_AFTER_IEND;
 }
 
 #if defined(PNG_WRITE_gAMA_SUPPORTED)
@@ -280,6 +345,16 @@ png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
    /* make sure we don't depend upon the order of PNG_COLOR_8 */
    if (color_type & PNG_COLOR_MASK_COLOR)
    {
+      int maxbits;
+
+      maxbits = color_type==PNG_COLOR_TYPE_PALETTE ? 8:png_ptr->usr_bit_depth;
+      if (sbit->red == 0 || sbit->red > maxbits || 
+          sbit->green == 0 || sbit->green > maxbits || 
+          sbit->blue == 0 || sbit->blue > maxbits)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
       buf[0] = sbit->red;
       buf[1] = sbit->green;
       buf[2] = sbit->blue;
@@ -287,12 +362,22 @@ png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
    }
    else
    {
+      if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
       buf[0] = sbit->gray;
       size = 1;
    }
 
    if (color_type & PNG_COLOR_MASK_ALPHA)
    {
+      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
       buf[size++] = sbit->alpha;
    }
 
@@ -311,22 +396,50 @@ png_write_cHRM ( png_structp png_ptr, double white_x, double white_y,
    png_byte buf[32];
 
    /* each value is saved int 1/100,000ths */
+   if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
+       white_x + white_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM white point specified");
+      return;
+   }
    itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
    png_save_uint_32(buf, itemp);
    itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
    png_save_uint_32(buf + 4, itemp);
+
+   if (red_x < 0 || red_x > 0.8 || red_y < 0 || red_y > 0.8 ||
+       red_x + red_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM red point specified");
+      return;
+   }
    itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
    png_save_uint_32(buf + 8, itemp);
    itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
    png_save_uint_32(buf + 12, itemp);
+
+   if (green_x < 0 || green_x > 0.8 || green_y < 0 || green_y > 0.8 ||
+       green_x + green_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM green point specified");
+      return;
+   }
    itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
    png_save_uint_32(buf + 16, itemp);
    itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
    png_save_uint_32(buf + 20, itemp);
+
+   if (blue_x < 0 || blue_x > 0.8 || blue_y < 0 || blue_y > 0.8 ||
+       blue_x + blue_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM blue point specified");
+      return;
+   }
    itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
    png_save_uint_32(buf + 24, itemp);
    itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
    png_save_uint_32(buf + 28, itemp);
+
    png_write_chunk(png_ptr, png_cHRM, buf, (png_uint_32)32);
 }
 #endif
@@ -341,6 +454,11 @@ png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
 
    if (color_type == PNG_COLOR_TYPE_PALETTE)
    {
+      if (num_trans <= 0 || num_trans > png_ptr->num_palette)
+      {
+         png_warning(png_ptr,"Invalid number of transparent colors specified");
+         return;
+      }
       /* write the chunk out as it is */
       png_write_chunk(png_ptr, png_tRNS, trans, (png_uint_32)num_trans);
    }
@@ -358,6 +476,10 @@ png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
       png_save_uint_16(buf + 4, tran->blue);
       png_write_chunk(png_ptr, png_tRNS, buf, (png_uint_32)6);
    }
+   else
+   {
+      png_warning(png_ptr, "Can't write tRNS with and alpha channel");
+   }
 }
 #endif
 
@@ -370,6 +492,11 @@ png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
 
    if (color_type == PNG_COLOR_TYPE_PALETTE)
    {
+      if (back->index > png_ptr->num_palette)
+      {
+         png_warning(png_ptr, "Invalid background palette index");
+         return;
+      }
       buf[0] = back->index;
       png_write_chunk(png_ptr, png_bKGD, buf, (png_uint_32)1);
    }
@@ -396,6 +523,12 @@ png_write_hIST(png_structp png_ptr, png_uint_16p hist, int number)
    int i;
    png_byte buf[3];
 
+   if (number <= 0 || number > png_ptr->num_palette)
+   {
+      png_warning(png_ptr, "Invalid number of histogram entries specified");
+      return;
+   }
+
    png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(number * 2));
    for (i = 0; i < number; i++)
    {
@@ -415,6 +548,19 @@ png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
    int key_len;
 
    key_len = png_strlen(key);
+
+   if (key_len == 0)
+   {
+      png_warning(png_ptr, "Invalid text keyword length");
+      return;
+   }
+   else if (key_len > 80)
+   {
+      png_warning(png_ptr, "Text keyword length restricted to 80 characters\n");
+      key[80] = '\0';
+      key_len = 80;
+   }
+
    /* make sure we count the 0 after the key */
    png_write_chunk_start(png_ptr, png_tEXt,
       (png_uint_32)(key_len + text_len + 1));
@@ -441,6 +587,24 @@ png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
 
    key_len = png_strlen(key);
 
+   if (key_len == 0)
+   {
+      png_warning(png_ptr, "Invalid text keyword length");
+      return;
+   }
+   else if (key_len > 80)
+   {
+      png_warning(png_ptr, "Text keyword length restricted to 80 characters\n");
+      key[80] = '\0';
+      key_len = 80;
+   }
+
+   if (compression != 0)
+   {
+      png_warning(png_ptr, "Only type 0 compression allowed for text\n");
+      compression = 0;
+   }
+
    /* we can't write the chunk until we find out how much data we have,
       which means we need to run the compresser first, and save the
       output.  This shouldn't be a problem, as the vast majority of
@@ -603,6 +767,9 @@ png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
 {
    png_byte buf[9];
 
+   if (unit_type >= PNG_RESOLUTION_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
+
    png_save_uint_32(buf, x_pixels_per_unit);
    png_save_uint_32(buf + 4, y_pixels_per_unit);
    buf[8] = (png_byte)unit_type;
@@ -620,6 +787,9 @@ png_write_oFFs(png_structp png_ptr, png_uint_32 x_offset,
 {
    png_byte buf[9];
 
+   if (unit_type >= PNG_OFFSET_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
+
    png_save_uint_32(buf, x_offset);
    png_save_uint_32(buf + 4, y_offset);
    buf[8] = (png_byte)unit_type;
@@ -636,6 +806,14 @@ png_write_tIME(png_structp png_ptr, png_timep mod_time)
 {
    png_byte buf[7];
 
+   if (mod_time->month  > 12 || mod_time->month  < 1 ||
+       mod_time->day    > 31 || mod_time->day    < 1 ||
+       mod_time->hour   > 23 || mod_time->second > 60)
+   {
+      png_warning(png_ptr, "Invalid time specified for tIME chunk");
+      return;
+   }
+
    png_save_uint_16(buf, mod_time->year);
    buf[2] = mod_time->month;
    buf[3] = mod_time->day;
@@ -656,15 +834,47 @@ png_write_start_row(png_structp png_ptr)
       (((png_uint_32)png_ptr->usr_channels *
       (png_uint_32)png_ptr->usr_bit_depth *
       png_ptr->width + 7) >> 3) + 1);
-   /* set up filtering buffers, if filtering */
+   png_ptr->row_buf[0] = 0;
-   if (png_ptr->do_filter)
+
+   /* set up filtering buffer, if using this filter */
+   if (png_ptr->do_filter & PNG_FILTER_SUB)
    {
+      png_ptr->sub_row = (png_bytep )png_large_malloc(png_ptr,
+         png_ptr->rowbytes + 1);
+      png_ptr->sub_row[0] = 1;  /* Set the row filter type */
+   }
+
+   /* We only need to keep the previous row if we are using one of these */
+   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
+   {
+     /* set up previous row buffer */
       png_ptr->prev_row = (png_bytep )png_large_malloc(png_ptr,
+         (((png_uint_32)png_ptr->usr_channels *
+         (png_uint_32)png_ptr->usr_bit_depth *
+         png_ptr->width + 7) >> 3) + 1);
+      png_memset(png_ptr->prev_row, 0, (((png_uint_32)png_ptr->usr_channels *
+         (png_uint_32)png_ptr->usr_bit_depth * png_ptr->width + 7) >> 3) + 1);
+
+      if (png_ptr->do_filter & PNG_FILTER_UP)
+      {
+         png_ptr->up_row = (png_bytep )png_large_malloc(png_ptr,
             png_ptr->rowbytes + 1);
-      png_memset(png_ptr->prev_row, 0, (png_size_t)png_ptr->rowbytes + 1);
+         png_ptr->up_row[0] = 2;  /* Set the row filter type */
-      png_ptr->save_row = (png_bytep )png_large_malloc(png_ptr,
+      }
+
+      if (png_ptr->do_filter & PNG_FILTER_AVG)
+      {
+         png_ptr->avg_row = (png_bytep )png_large_malloc(png_ptr,
             png_ptr->rowbytes + 1);
-      png_memset(png_ptr->save_row, 0, (png_size_t)png_ptr->rowbytes + 1);
+         png_ptr->avg_row[0] = 3;  /* Set the row filter type */
+      }
+
+      if (png_ptr->do_filter & PNG_FILTER_PAETH)
+      {
+         png_ptr->paeth_row = (png_bytep )png_large_malloc(png_ptr,
+            png_ptr->rowbytes + 1);
+         png_ptr->paeth_row[0] = 4;  /* Set the row filter type */
+      }
    }
 
    /* if interlaced, we need to set up width and height of pass */
@@ -736,9 +946,11 @@ png_write_finish_row(png_structp png_ptr)
 
       }
 
-      /* reset filter row */
+      /* reset the row above the image for the next pass */
       if (png_ptr->prev_row)
-         png_memset(png_ptr->prev_row, 0, (png_size_t)png_ptr->rowbytes + 1);
+         png_memset(png_ptr->prev_row, 0, (((png_uint_32)png_ptr->usr_channels *
+            (png_uint_32)png_ptr->usr_bit_depth * png_ptr->width + 7) >> 3) + 1);
+
       /* if we have more data to get, go get it */
       if (png_ptr->pass < 7)
          return;
@@ -935,205 +1147,143 @@ png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
 }
 #endif
 
-/* this filters the row.  Both row and prev_row have space at the
+/* this filters the row, chooses which filter to use, if it has not already
-   first byte for the filter byte. */
+ * been given by the application, and then writes the row out with the
+ * chosen filter */
 void
-png_write_filter_row(png_row_infop row_info, png_bytep row,
+png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
-   png_bytep prev_row)
 {
-   int minf, bpp;
+   png_bytep prev_row, best_row, row_buf;
-   png_uint_32 i, v;
+   png_uint_32 mins;
-   png_uint_32 s0, s1, s2, s3, s4, mins;
+   int bpp;
-   png_bytep rp, pp, cp, lp;
 
    /* find out how many bytes offset each pixel is */
    bpp = (row_info->pixel_depth + 7) / 8;
-   if (bpp < 1)
+
-      bpp = 1;
+   prev_row = png_ptr->prev_row;
+   best_row = row_buf = png_ptr->row_buf;
+   mins = 0xffffffff;
 
    /* the prediction method we use is to find which method provides
       the smallest value when summing the abs of the distances from
       zero using anything >= 128 as negitive numbers. */
-   s0 = s1 = s2 = s3 = s4 = 0;
 
-   for (i = 0, rp = row + 1, pp = prev_row + 1, lp = row + 1 - bpp,
+   /* We don't need to test the 'no filter' case if this is the only filter
-         cp = prev_row + 1 - bpp;
+    * that has been chosen, as it doesn't actually do anything to the data. */
-      i < bpp; i++, rp++, pp++, lp++, cp++)
+   if (png_ptr->do_filter & PNG_FILTER_NONE &&
+       png_ptr->do_filter != PNG_FILTER_NONE)
+   {
+      png_bytep rp;
+      png_uint_32 sum = 0;
+      int i, v;
+
+      for (i = 0, rp = row_buf + 1; i < row_info->rowbytes; i++, rp++)
       {
-      /* check none filter */
          v = *rp;
-      if (v < 128)
+         sum += (v < 128) ? v : 256 - v;
-         s0 += v;
+      }
-      else
+      mins = sum;
-         s0 += 256 - v;
-
-      /* check up filter */
-      v = (png_byte)(((int)*rp - (int)*pp) & 0xff);
-
-      if (v < 128)
-         s2 += v;
-      else
-         s2 += 256 - v;
-
-      /* check avg filter */
-      v = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
-
-      if (v < 128)
-         s3 += v;
-      else
-         s3 += 256 - v;
    }
 
-   /* some filters are same until we get past bpp */
-   s1 = s0;
-   s4 = s2;
-
-   for (; i < row_info->rowbytes; i++, rp++, pp++, lp++, cp++)
-   {
-      int a, b, c, pa, pb, pc, p;
-
-      /* check none filter */
-      v = *rp;
-      if (v < 128)
-         s0 += v;
-      else
-         s0 += 256 - v;
-
-      /* check sub filter */
-      v = (png_byte)(((int)*rp - (int)*lp) & 0xff);
-
-      if (v < 128)
-         s1 += v;
-      else
-         s1 += 256 - v;
-
-      /* check up filter */
-      v = (png_byte)(((int)*rp - (int)*pp) & 0xff);
-
-      if (v < 128)
-         s2 += v;
-      else
-         s2 += 256 - v;
-
-      /* check avg filter */
-      v = (png_byte)(((int)*rp - (((int)*pp + (int)*lp) / 2)) & 0xff);
-
-      if (v < 128)
-         s3 += v;
-      else
-         s3 += 256 - v;
-
-      /* check paeth filter */
-      b = *pp;
-      c = *cp;
-      a = *lp;
-      p = a + b - c;
-      pa = abs(p - a);
-      pb = abs(p - b);
-      pc = abs(p - c);
-
-      if (pa <= pb && pa <= pc)
-         p = a;
-      else if (pb <= pc)
-         p = b;
-      else
-         p = c;
-
-      v = (png_byte)(((int)*rp - p) & 0xff);
-
-      if (v < 128)
-         s4 += v;
-      else
-         s4 += 256 - v;
-   }
-
-   mins = s0;
-   minf = 0;
-
-   if (s1 < mins)
-   {
-      mins = s1;
-      minf = 1;
-   }
-
-   if (s2 < mins)
-   {
-      mins = s2;
-      minf = 2;
-   }
-
-   if (s3 < mins)
-   {
-      mins = s3;
-      minf = 3;
-   }
-
-   if (s4 < mins)
-   {
-      minf = 4;
-   }
-
-   /* set filter byte */
-   row[0] = (png_byte)minf;
-
-   /* do filter */
-   switch (minf)
-   {
    /* sub filter */
-      case 1:
+   if (png_ptr->do_filter & PNG_FILTER_SUB)
-         for (i = bpp, rp = row + (png_size_t)row_info->rowbytes,
-            lp = row + (png_size_t)row_info->rowbytes - bpp;
-            i < row_info->rowbytes; i++, rp--, lp--)
    {
-            *rp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+      png_bytep rp, dp, lp;
+      png_uint_32 sum = 0;
+      int i, v;
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+           i++, rp++, dp++)
+      {
+         v = *dp = *rp;
+
+         sum += (v < 128) ? v : 256 - v;
       }
-         break;
+      for (lp = row_buf + 1; i < row_info->rowbytes; i++, rp++, lp++, dp++)
+      {
+         v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+      }
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->sub_row;
+      }
+   }
+
    /* up filter */
-      case 2:
+   if (png_ptr->do_filter & PNG_FILTER_UP)
-         for (i = 0, rp = row + (png_size_t)row_info->rowbytes,
-            pp = prev_row + (png_size_t)row_info->rowbytes;
-            i < row_info->rowbytes; i++, rp--, pp--)
    {
-            *rp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+      png_bytep rp, dp, pp;
+      png_uint_32 sum = 0;
+      int i, v;
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+           pp = prev_row + 1; i < row_info->rowbytes; i++, rp++, pp++, dp++)
+      {
+         v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
       }
-         break;
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->up_row;
+      }
+   }
+
    /* avg filter */
-      case 3:
+   if (png_ptr->do_filter & PNG_FILTER_AVG)
-         for (i = row_info->rowbytes,
-            rp = row + (png_size_t)row_info->rowbytes,
-            pp = prev_row + (png_size_t)row_info->rowbytes,
-            lp = row + (png_size_t)row_info->rowbytes - bpp;
-            i > bpp; i--, rp--, lp--, pp--)
    {
-            *rp = (png_byte)(((int)*rp - (((int)*lp + (int)*pp) /
+      png_bytep rp, dp, pp, lp;
-               2)) & 0xff);
+      png_uint_32 sum = 0;
-         }
+      int i, v;
-         for (; i > 0; i--, rp--, pp--)
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+           pp = prev_row + 1; i < bpp; i++, rp++, pp++, dp++)
       {
-            *rp = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
+         v = *dp = (png_byte)(((int)*rp - ((int)*pp / 2)) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
       }
-         break;
+      for (lp = row_buf + 1; i < row_info->rowbytes;
+           i++, rp++, pp++, lp++, dp++)
+      {
+         v = *dp = (png_byte)(((int)*rp - (((int)*pp + (int)*lp) / 2)) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+      }
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->avg_row;
+      }
+   }
+
    /* paeth filter */
-      case 4:
+   if (png_ptr->do_filter & PNG_FILTER_PAETH)
-         for (i = row_info->rowbytes,
+   {
-            rp = row + (png_size_t)row_info->rowbytes,
+      png_bytep rp, dp, pp, cp, lp;
-            pp = prev_row + (png_size_t)row_info->rowbytes,
+      png_uint_32 sum = 0;
-            lp = row + (png_size_t)row_info->rowbytes - bpp,
+      int i, v;
-            cp = prev_row + (png_size_t)row_info->rowbytes - bpp;
+
-            i > 0; i--, rp--, lp--, pp--, cp--)
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+           pp = prev_row + 1; i < bpp; i++, rp++, pp++, dp++)
+      {
+         v = *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+      }
+      for (lp = row_buf + 1, cp = prev_row + 1; i < row_info->rowbytes;
+           i++, rp++, pp++, lp++, dp++, cp++)
       {
          int a, b, c, pa, pb, pc, p;
 
          b = *pp;
-            if (i > bpp)
-            {
          c = *cp;
          a = *lp;
-            }
+
-            else
-            {
-               a = c = 0;
-            }
          p = a + b - c;
          pa = abs(p - a);
          pb = abs(p - b);
@@ -1146,9 +1296,66 @@ png_write_filter_row(png_row_infop row_info, png_bytep row,
          else
             p = c;
 
-            *rp = (png_byte)(((int)*rp - p) & 0xff);
+         v = *dp = (png_byte)(((int)*rp - p) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
       }
-         break;
+      if (sum < mins)
+      {
+         best_row = png_ptr->paeth_row;
       }
    }
 
+   /* Do the actual writing of the filtered row data from the chosen filter */
+   png_write_filtered_row(png_ptr, best_row);
+}
+
+
+/* do the actual writing of a filtered row */
+void
+png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
+{
+   /* set up the zlib input buffer */
+   png_ptr->zstream->next_in = filtered_row;
+   png_ptr->zstream->avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
+   /* repeat until we have compressed all the data */
+   do
+   {
+      int ret; /* return of zlib */
+
+      /* compress the data */
+      ret = deflate(png_ptr->zstream, Z_NO_FLUSH);
+      /* check for compression errors */
+      if (ret != Z_OK)
+      {
+         if (png_ptr->zstream->msg)
+            png_error(png_ptr, png_ptr->zstream->msg);
+         else
+            png_error(png_ptr, "zlib error");
+      }
+
+      /* see if it is time to write another IDAT */
+      if (!png_ptr->zstream->avail_out)
+      {
+         /* write the IDAT and reset the zlib output buffer */
+         png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+         png_ptr->zstream->next_out = png_ptr->zbuf;
+         png_ptr->zstream->avail_out = (uInt)png_ptr->zbuf_size;
+      }
+   /* repeat until all data has been compressed */
+   } while (png_ptr->zstream->avail_in);
+
+   /* finish row - updates counters and flushes zlib if last row */
+   png_write_finish_row(png_ptr);
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+   png_ptr->flush_rows++;
+
+   if (png_ptr->flush_dist > 0 &&
+       png_ptr->flush_rows >= png_ptr->flush_dist)
+   {
+      png_write_flush(png_ptr);
+   }
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+}
+

readme.txt

@@ -1,41 +1,56 @@
-readme.txt - for libpng 0.88
+readme.txt - for libpng 0.89
 
-This is a bug fix for the second beta version of libpng 1.0, and
+This is a bug fix for the third beta version of libpng 1.0.  The
-a more secure progressive (push) reader.  The progressive reader
+changes from libpng-0.88 are bug fixes and some changes to the
-hasn't been tested as much as the pull reader, but seems to work ok.
+API itself to increase robustness with shared libraries.  This
+release is based on libpng-0.88, but has been modified from that
+version by Andreas Dilger <adilger@enel.ucalgary.ca> because the
+original author, Guy Schalnat, has not been able to keep up with
+the time demands of maintaining this library.
 
-I've implemented the callback functions for the error/warning
+The callback functions for the error/warning messages have changed
-messages and the input/output.  See the libpng.txt
+since the last release because their implementation was broken,
-for details.  I've also added defines to support medium memory
+and it was thought best to change the API itself (which was only
-models, so every type now has pointer defines.  For example,
+introduced in libpng-0.88 itself) to alert the user to the change,
-a pointer to the png_struct is now png_structp, while a double
+rather than mislead the user into thinking their application was
-pointer is now png_structpp.  The old way should work, but I'll
+OK after re-compiling.  This means that calls to png_set_message_fn()
-be using the new way from now on in all my examples.  Those of
+no longer exist, because the previously suggested method of calling
-you doing medium memory model or changing the error/warning
+them before png_read_init() or png_write_init() is now ineffective.
-or input/output functions should try these and report back to
-me any problems.
 
-I've tried to incorporate all the changes and makefiles everyone
+The preferred method of setting the error and warning callbacks
-sent me.  However, I may of lost some in the flood.  If you sent
+has been incorporated into the allocation of the png_struct and
-me a change and I didn't put it in, send it again.  Sorry.
+info_struct itself, which allow them to be safely used during the
+initialization of the structure, as well as to keep the size of
+the png_struct internal to the library, rather than at compile time
+of the application.  This will hopefully remove any problems with
+dynamically linked libraries, and should be considered the preferred
+method of creating these structures, although the previous
+initialization API is still available for compatibility.  See libpng.txt
+for more information on the new API.
+
+The changes made to the library, and bugs fixed are based on discussions
+on the PNG implementation mailing list <png-implement@dworking.wustl.edu>
+and not on material submitted to Guy.
 
 For a detailed description on using libpng, read libpng.txt.  For
 usage information and restrictions (what little they are) on libpng,
 see png.h.  For a description on using zlib (the compression library
 used by libpng) and zlib's restrictions, see zlib.h
 
-I have included a general makefile, but you may have to modify it
+I have included a general makefile, as well as several machine and compiler
-for your own needs.
+specific ones, but you may have to modify one for your own needs.
 
 You will need zlib 0.95 or later to run this.  zlib is a compression
 library that is useful for more things then just png files.  If
-you need a compression library, check out zlib.h
+you need a compression library, check out zlib.h.  There was a bug in
+zlib <= 0.99 which caused it to generate invalid compression streams
+on some occasions.  Later versions of zlib do not have this problem.
 
 zlib should be available at the same place that libpng is.
 If not, it should be at ftp.uu.net in /graphics/png
 Eventually, it will be at ftp.uu.net in /pub/archiving/zip/zlib
 
-You will also want a copy of the PNG specification.  It should
+You may also want a copy of the PNG specification.  It should
 be available at the same place you picked up libpng.  If it is
 not there, try ftp.uu.net in the /graphics/png directory.
 
@@ -55,17 +70,18 @@ Finally, if you get any warning messages when compiling libpng
 (note: not zlib), and they are easy to fix, I'd appreciate the
 fix.  Please mention "libpng" somewhere in the subject line.  Thanks.
 
-You can reach me at:
+This release was created and will be supported by myself, and the
+PNG group.
+
+adilger@enel.ucalgary.ca
+png-implement@dworkin.wustl.edu
+
+You can reach Guy, the original libpng author, at (internet preferred):
 
 internet: schalnat@group42.com
 CompuServe: 75501,1625
 
-I tend to check my CompuServe account very infrequently, so you may
+Please do not send general questions about PNG.  Send them to
-want to use the internet account.  If I don't answer your email
-immediately, please be patient.  If you don't receive a reply within
-a week, you may want to write and ask if I got the first email.
-
-Please do not send me general questions about PNG.  Send them to
 the address in the specification.  At the same time, please do
 not send libpng questions to that address, send them to me.  I'll
 get them in the end anyway.  If you have a question about something